feat(dashboard): global (All Libraries) preferences scope

The dashboard's All Libraries view could render sections across every
library but could not persist its own preferences: the PUT required a
UUID library_id, and the prefs GET-without-library_id matched an
arbitrary library's row through a loose NULL OR-clause.

Storage: a dedicated user_dashboard_preferences_global table (one row
per user, user_id PK → users CASCADE) instead of a NULL/sentinel
library_id — chosen over both because (a) the column's FK to libraries
rules out a sentinel UUID without dropping the constraint or minting a
fake library row, and (b) intent becomes structural: only the explicit
global path writes that table, so a buggy or outside-the-API write can
never masquerade as global. System and user collections are
user-scoped, so the order/hidden arrays are library-independent and
valid in this scope.

API: PUT /api/dashboard/preferences binds library_id as *string —
JSON null/absent = global, empty string = 400 (a lost value must stay
loud, not silently clobber the global scope), valid UUID = per-library
(unchanged). GET without library_id now returns the global row instead
of an arbitrary one; the per-library query's dead NULL OR-arm is
removed. GET /sections keeps requiring library_id for per-library
views and aggregates across libraries when absent (unchanged).

Tests: global save/update-dedupe/read round-trip, empty-string 400,
global-vs-per-library independence. Two suite failures are the
handoff's documented pre-existing rot (duplicate system collections in
the dev DB; a sections test expecting a 400 the handler never
implemented) — reproduced and confirmed unrelated to this change.
Live-verified on the dev stack: null save 200 x2 with a single row
updated, empty string 400, global read carries the second save.

cmd/server/tests/dashboard_integration_test.go

@@ -258,6 +258,151 @@ func (s *DashboardIntegrationTestSuite) TestRestoreSystemCollection_ValidNames()
 	}
 }
 
+func (s *DashboardIntegrationTestSuite) TestUpdatePreferences_GlobalScope() {
+	token := s.setup.Token
+
+	// Absent library_id (JSON null after omit) = the global All Libraries
+	// scope: stored in user_dashboard_preferences_global, one row per user.
+	reqBody := map[string]interface{}{
+		"hidden_collections": []string{"not-started"},
+		"collection_order":   []string{"continue-reading", "recently-added"},
+		"items_per_section":  15,
+	}
+	body, _ := json.Marshal(reqBody)
+	req, _ := http.NewRequest("PUT", s.setup.Server.URL+"/api/dashboard/preferences", bytes.NewBuffer(body))
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+token)
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	require.NoError(s.T(), err)
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(resp.Body)
+
+	assert.Equal(s.T(), http.StatusOK, resp.StatusCode)
+
+	// Second global save with different values: must UPDATE the same row
+	// (the old ON CONFLICT (user_id, library_id) never fired for NULLs and
+	// would have minted a duplicate per save).
+	reqBody["items_per_section"] = 25
+	body, _ = json.Marshal(reqBody)
+	req, _ = http.NewRequest("PUT", s.setup.Server.URL+"/api/dashboard/preferences", bytes.NewBuffer(body))
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+token)
+	resp, err = client.Do(req)
+	require.NoError(s.T(), err)
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(resp.Body)
+	assert.Equal(s.T(), http.StatusOK, resp.StatusCode)
+
+	// Reading prefs without library_id returns the global row (not some
+	// arbitrary library's).
+	req, _ = http.NewRequest("GET", s.setup.Server.URL+"/api/dashboard/preferences", nil)
+	req.Header.Set("Authorization", "Bearer "+token)
+	resp, err = client.Do(req)
+	require.NoError(s.T(), err)
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(resp.Body)
+	assert.Equal(s.T(), http.StatusOK, resp.StatusCode)
+
+	var prefs map[string]interface{}
+	err = json.NewDecoder(resp.Body).Decode(&prefs)
+	require.NoError(s.T(), err)
+	assert.Equal(s.T(), float64(25), prefs["items_per_section"], "global row should carry the second save")
+}
+
+func (s *DashboardIntegrationTestSuite) TestUpdatePreferences_EmptyLibraryIDRejected() {
+	token := s.setup.Token
+
+	// Empty string is a LOST value (a client bug), never a scope — must
+	// stay a loud 400 rather than silently writing the global scope.
+	reqBody := map[string]interface{}{
+		"library_id":         "",
+		"hidden_collections": []string{},
+		"collection_order":   []string{},
+		"items_per_section":  20,
+	}
+	body, _ := json.Marshal(reqBody)
+	req, _ := http.NewRequest("PUT", s.setup.Server.URL+"/api/dashboard/preferences", bytes.NewBuffer(body))
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+token)
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	require.NoError(s.T(), err)
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(resp.Body)
+
+	assert.Equal(s.T(), http.StatusBadRequest, resp.StatusCode)
+}
+
+func (s *DashboardIntegrationTestSuite) TestGetPreferences_GlobalAndPerLibraryIndependent() {
+	token := s.setup.Token
+	libraryID := createTestLibraryWithFolder(s.T(), s.setup.Server, token, "Prefs Scope Library", false)
+
+	// Global scope: 15.
+	globalBody, _ := json.Marshal(map[string]interface{}{
+		"hidden_collections": []string{},
+		"collection_order":   []string{},
+		"items_per_section":  15,
+	})
+	req, _ := http.NewRequest("PUT", s.setup.Server.URL+"/api/dashboard/preferences", bytes.NewBuffer(globalBody))
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+token)
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	require.NoError(s.T(), err)
+	resp.Body.Close()
+	require.Equal(s.T(), http.StatusOK, resp.StatusCode)
+
+	// Per-library scope: 30. Must not bleed into global or vice versa.
+	libBody, _ := json.Marshal(map[string]interface{}{
+		"library_id":         libraryID,
+		"hidden_collections": []string{},
+		"collection_order":   []string{},
+		"items_per_section":  30,
+	})
+	req, _ = http.NewRequest("PUT", s.setup.Server.URL+"/api/dashboard/preferences", bytes.NewBuffer(libBody))
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+token)
+	resp, err = client.Do(req)
+	require.NoError(s.T(), err)
+	resp.Body.Close()
+	require.Equal(s.T(), http.StatusOK, resp.StatusCode)
+
+	// Per-library read.
+	req, _ = http.NewRequest("GET", s.setup.Server.URL+"/api/dashboard/preferences?library_id="+libraryID, nil)
+	req.Header.Set("Authorization", "Bearer "+token)
+	resp, err = client.Do(req)
+	require.NoError(s.T(), err)
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(resp.Body)
+	require.Equal(s.T(), http.StatusOK, resp.StatusCode)
+	var libPrefs map[string]interface{}
+	err = json.NewDecoder(resp.Body).Decode(&libPrefs)
+	require.NoError(s.T(), err)
+	assert.Equal(s.T(), float64(30), libPrefs["items_per_section"], "per-library scope should read its own row")
+
+	// Global read.
+	req, _ = http.NewRequest("GET", s.setup.Server.URL+"/api/dashboard/preferences", nil)
+	req.Header.Set("Authorization", "Bearer "+token)
+	resp, err = client.Do(req)
+	require.NoError(s.T(), err)
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(resp.Body)
+	require.Equal(s.T(), http.StatusOK, resp.StatusCode)
+	var globalPrefs map[string]interface{}
+	err = json.NewDecoder(resp.Body).Decode(&globalPrefs)
+	require.NoError(s.T(), err)
+	assert.Equal(s.T(), float64(15), globalPrefs["items_per_section"], "global scope should stay independent")
+}
+
 func TestDashboardIntegrationTestSuite(t *testing.T) {
 	suite.Run(t, new(DashboardIntegrationTestSuite))
 }

database/schema/schema.sql

@@ -1160,6 +1160,20 @@ CREATE TABLE IF NOT EXISTS user_dashboard_preferences (
 -- Index for fast lookups
 CREATE INDEX IF NOT EXISTS idx_dashboard_prefs_user_library ON user_dashboard_preferences(user_id, library_id);
 
+-- Global (all-libraries) dashboard preferences: exactly one row per user.
+-- Backs the dashboard's "All Libraries" view (library_id NULL convention
+-- rejected: the upsert's ON CONFLICT cannot dedupe NULLs and intent would
+-- be invisible — a dedicated table makes the scope structural). System
+-- and user collections are user-scoped, so collection_order/
+-- hidden_collections IDs are library-independent and valid in this scope.
+CREATE TABLE IF NOT EXISTS user_dashboard_preferences_global (
+    user_id UUID PRIMARY KEY REFERENCES users(id) ON DELETE CASCADE,
+    hidden_collections TEXT[] DEFAULT '{}',
+    collection_order TEXT[] DEFAULT '{}',
+    items_per_section INT DEFAULT 20,
+    updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
 -- Create collection_items table (which books belong to each collection)
 CREATE TABLE IF NOT EXISTS collection_items (
     id UUID PRIMARY KEY DEFAULT gen_random_uuid(),

internal/database/models.go

@@ -538,6 +538,14 @@ type UserDashboardPreferences struct {
 	UpdatedAt         pgtype.Timestamptz `db:"updated_at" json:"updated_at"`
 }
 
+type UserDashboardPreferencesGlobal struct {
+	UserID            pgtype.UUID        `db:"user_id" json:"user_id"`
+	HiddenCollections []string           `db:"hidden_collections" json:"hidden_collections"`
+	CollectionOrder   []string           `db:"collection_order" json:"collection_order"`
+	ItemsPerSection   pgtype.Int4        `db:"items_per_section" json:"items_per_section"`
+	UpdatedAt         pgtype.Timestamptz `db:"updated_at" json:"updated_at"`
+}
+
 type Users struct {
 	ID           pgtype.UUID        `db:"id" json:"id"`
 	Email        string             `db:"email" json:"email"`

internal/database/querier.go

@@ -174,6 +174,10 @@ type Querier interface {
 	// CAROUSEL-STYLE DASHBOARD
 	// ============================================
 	// Dashboard preferences queries
+	// The handler routes by scope: a Valid library_id targets the per-library
+	// table below; an absent one targets user_dashboard_preferences_global
+	// (the "All Libraries" view). Never pass NULL here — the loose NULL match
+	// was removed because it returned an arbitrary library's row.
 	GetDashboardPreferences(ctx context.Context, arg GetDashboardPreferencesParams) (UserDashboardPreferences, error)
 	GetDevice(ctx context.Context, id pgtype.UUID) (Devices, error)
 	GetDeviceByAuthToken(ctx context.Context, authToken string) (Devices, error)
@@ -200,6 +204,8 @@ type Querier interface {
 	GetFailedSyncQueueItems(ctx context.Context, limit int32) ([]SyncQueue, error)
 	GetFirstAdmin(ctx context.Context) (pgtype.UUID, error)
 	GetFirstAdminExclude(ctx context.Context, id pgtype.UUID) (GetFirstAdminExcludeRow, error)
+	// Global (all-libraries) scope: exactly one row per user.
+	GetGlobalDashboardPreferences(ctx context.Context, userID pgtype.UUID) (UserDashboardPreferencesGlobal, error)
 	GetHashConflict(ctx context.Context, id pgtype.UUID) (HashConflicts, error)
 	GetKoboEntitlementByContentId(ctx context.Context, arg GetKoboEntitlementByContentIdParams) (GetKoboEntitlementByContentIdRow, error)
 	GetKoboEntitlementByEntitlementId(ctx context.Context, arg GetKoboEntitlementByEntitlementIdParams) (GetKoboEntitlementByEntitlementIdRow, error)
@@ -503,6 +509,7 @@ type Querier interface {
 	UpdateUserTimezone(ctx context.Context, arg UpdateUserTimezoneParams) error
 	UpdateUsername(ctx context.Context, arg UpdateUsernameParams) error
 	UpsertDashboardPreferences(ctx context.Context, arg UpsertDashboardPreferencesParams) (UserDashboardPreferences, error)
+	UpsertGlobalDashboardPreferences(ctx context.Context, arg UpsertGlobalDashboardPreferencesParams) (UserDashboardPreferencesGlobal, error)
 	UpsertPanelData(ctx context.Context, arg UpsertPanelDataParams) (PanelData, error)
 	UpsertReaderSettings(ctx context.Context, arg UpsertReaderSettingsParams) (ReaderSettings, error)
 	UpsertSystemSetting(ctx context.Context, arg UpsertSystemSettingParams) (SystemSettings, error)

internal/database/queries.sql.go

@@ -3276,7 +3276,7 @@ func (q *Queries) GetContinueSeriesItems(ctx context.Context, arg GetContinueSer
 const GetDashboardPreferences = `-- name: GetDashboardPreferences :one
 
 SELECT id, user_id, library_id, hidden_collections, collection_order, items_per_section, created_at, updated_at FROM user_dashboard_preferences
-WHERE user_id = $1 AND ($2::uuid IS NULL OR library_id = $2::uuid)
+WHERE user_id = $1 AND library_id = $2::uuid
 `
 
 type GetDashboardPreferencesParams struct {
@@ -3288,6 +3288,10 @@ type GetDashboardPreferencesParams struct {
 // CAROUSEL-STYLE DASHBOARD
 // ============================================
 // Dashboard preferences queries
+// The handler routes by scope: a Valid library_id targets the per-library
+// table below; an absent one targets user_dashboard_preferences_global
+// (the "All Libraries" view). Never pass NULL here — the loose NULL match
+// was removed because it returned an arbitrary library's row.
 func (q *Queries) GetDashboardPreferences(ctx context.Context, arg GetDashboardPreferencesParams) (UserDashboardPreferences, error) {
 	row := q.db.QueryRow(ctx, GetDashboardPreferences, arg.UserID, arg.LibraryID)
 	var i UserDashboardPreferences
@@ -3846,6 +3850,25 @@ func (q *Queries) GetFirstAdminExclude(ctx context.Context, id pgtype.UUID) (Get
 	return i, err
 }
 
+const GetGlobalDashboardPreferences = `-- name: GetGlobalDashboardPreferences :one
+SELECT user_id, hidden_collections, collection_order, items_per_section, updated_at FROM user_dashboard_preferences_global
+WHERE user_id = $1
+`
+
+// Global (all-libraries) scope: exactly one row per user.
+func (q *Queries) GetGlobalDashboardPreferences(ctx context.Context, userID pgtype.UUID) (UserDashboardPreferencesGlobal, error) {
+	row := q.db.QueryRow(ctx, GetGlobalDashboardPreferences, userID)
+	var i UserDashboardPreferencesGlobal
+	err := row.Scan(
+		&i.UserID,
+		&i.HiddenCollections,
+		&i.CollectionOrder,
+		&i.ItemsPerSection,
+		&i.UpdatedAt,
+	)
+	return i, err
+}
+
 const GetHashConflict = `-- name: GetHashConflict :one
 SELECT id, library_id, file_sha256, status, resolution, resolved_by, created_at, resolved_at FROM hash_conflicts WHERE id = $1
 `
@@ -13839,6 +13862,43 @@ func (q *Queries) UpsertDashboardPreferences(ctx context.Context, arg UpsertDash
 	return i, err
 }
 
+const UpsertGlobalDashboardPreferences = `-- name: UpsertGlobalDashboardPreferences :one
+INSERT INTO user_dashboard_preferences_global (user_id, hidden_collections, collection_order, items_per_section)
+VALUES ($1, $2, $3, $4)
+ON CONFLICT (user_id)
+DO UPDATE SET
+    hidden_collections = EXCLUDED.hidden_collections,
+    collection_order = EXCLUDED.collection_order,
+    items_per_section = EXCLUDED.items_per_section,
+    updated_at = NOW()
+RETURNING user_id, hidden_collections, collection_order, items_per_section, updated_at
+`
+
+type UpsertGlobalDashboardPreferencesParams struct {
+	UserID            pgtype.UUID `db:"user_id" json:"user_id"`
+	HiddenCollections []string    `db:"hidden_collections" json:"hidden_collections"`
+	CollectionOrder   []string    `db:"collection_order" json:"collection_order"`
+	ItemsPerSection   pgtype.Int4 `db:"items_per_section" json:"items_per_section"`
+}
+
+func (q *Queries) UpsertGlobalDashboardPreferences(ctx context.Context, arg UpsertGlobalDashboardPreferencesParams) (UserDashboardPreferencesGlobal, error) {
+	row := q.db.QueryRow(ctx, UpsertGlobalDashboardPreferences,
+		arg.UserID,
+		arg.HiddenCollections,
+		arg.CollectionOrder,
+		arg.ItemsPerSection,
+	)
+	var i UserDashboardPreferencesGlobal
+	err := row.Scan(
+		&i.UserID,
+		&i.HiddenCollections,
+		&i.CollectionOrder,
+		&i.ItemsPerSection,
+		&i.UpdatedAt,
+	)
+	return i, err
+}
+
 const UpsertPanelData = `-- name: UpsertPanelData :one
 INSERT INTO panel_data (media_item_id, page_number, detection_method, panels)
 VALUES ($1, $2, $3, $4)

internal/database/queries/queries.sql

@@ -2435,9 +2435,13 @@ LIMIT $1 OFFSET $2;
 -- ============================================
 
 -- Dashboard preferences queries
+-- The handler routes by scope: a Valid library_id targets the per-library
+-- table below; an absent one targets user_dashboard_preferences_global
+-- (the "All Libraries" view). Never pass NULL here — the loose NULL match
+-- was removed because it returned an arbitrary library's row.
 -- name: GetDashboardPreferences :one
 SELECT * FROM user_dashboard_preferences
-WHERE user_id = sqlc.narg('user_id') AND (sqlc.narg('library_id')::uuid IS NULL OR library_id = sqlc.narg('library_id')::uuid);
+WHERE user_id = sqlc.narg('user_id') AND library_id = sqlc.narg('library_id')::uuid;
 
 -- name: UpsertDashboardPreferences :one
 INSERT INTO user_dashboard_preferences (user_id, library_id, hidden_collections, collection_order, items_per_section)
@@ -2459,6 +2463,22 @@ SET hidden_collections = $2,
 WHERE user_id = $1 AND library_id = $5
 RETURNING *;
 
+-- Global (all-libraries) scope: exactly one row per user.
+-- name: GetGlobalDashboardPreferences :one
+SELECT user_id, hidden_collections, collection_order, items_per_section, updated_at FROM user_dashboard_preferences_global
+WHERE user_id = $1;
+
+-- name: UpsertGlobalDashboardPreferences :one
+INSERT INTO user_dashboard_preferences_global (user_id, hidden_collections, collection_order, items_per_section)
+VALUES ($1, $2, $3, $4)
+ON CONFLICT (user_id)
+DO UPDATE SET
+    hidden_collections = EXCLUDED.hidden_collections,
+    collection_order = EXCLUDED.collection_order,
+    items_per_section = EXCLUDED.items_per_section,
+    updated_at = NOW()
+RETURNING user_id, hidden_collections, collection_order, items_per_section, updated_at;
+
 -- Dashboard collections queries
 -- name: GetSystemCollectionsForDashboard :many
 SELECT * FROM collections

internal/handlers/dashboard.go

@@ -75,7 +75,9 @@ func (h *DashboardHandler) UpdatePreferences(c *echo.Context) error {
 	userUUID := uuid.UUID(user.ID.Bytes)
 
 	var req struct {
-		LibraryID         string   `json:"library_id"`
+		// nil (JSON null/absent) = the global All Libraries scope;
+		// empty string is a LOST value, not a scope — rejected loudly.
+		LibraryID         *string  `json:"library_id"`
 		HiddenCollections []string `json:"hidden_collections"`
 		CollectionOrder   []string `json:"collection_order"`
 		ItemsPerSection   int      `json:"items_per_section"`
@@ -85,9 +87,16 @@ func (h *DashboardHandler) UpdatePreferences(c *echo.Context) error {
 		return c.JSON(http.StatusBadRequest, map[string]string{"error": "Invalid request"})
 	}
 
-	libUUID, err := uuid.Parse(req.LibraryID)
-	if err != nil {
-		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid library_id"})
+	var libUUID pgtype.UUID
+	if req.LibraryID != nil {
+		if *req.LibraryID == "" {
+			return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid library_id"})
+		}
+		parsed, err := uuid.Parse(*req.LibraryID)
+		if err != nil {
+			return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid library_id"})
+		}
+		libUUID = pgtype.UUID{Bytes: parsed, Valid: true}
 	}
 
 	// Sanitize preferences (remove duplicates)
@@ -97,7 +106,7 @@ func (h *DashboardHandler) UpdatePreferences(c *echo.Context) error {
 
 	prefs, err := h.dashboardService.UpsertDashboardPreferences(c.Request().Context(), database.UpsertDashboardPreferencesParams{
 		UserID:            pgtype.UUID{Bytes: userUUID, Valid: true},
-		LibraryID:         pgtype.UUID{Bytes: libUUID, Valid: true},
+		LibraryID:         libUUID,
 		HiddenCollections: req.HiddenCollections,
 		CollectionOrder:   req.CollectionOrder,
 		ItemsPerSection:   pgtype.Int4{Int32: int32(req.ItemsPerSection), Valid: true},

internal/services/dashboard_service.go

@@ -376,6 +376,22 @@ func (s *DashboardService) getUserCollectionItems(ctx context.Context, coll data
 }
 
 func (s *DashboardService) GetDashboardPreferences(ctx context.Context, userID uuid.UUID, libraryID pgtype.UUID) (database.UserDashboardPreferences, error) {
+	// Absent library = the global (All Libraries) scope: a separate
+	// one-row-per-user table, so an accidental per-library write can never
+	// masquerade as global.
+	if !libraryID.Valid {
+		g, err := s.db.GetGlobalDashboardPreferences(ctx, pgtype.UUID{Bytes: userID, Valid: true})
+		if err != nil {
+			return database.UserDashboardPreferences{}, err
+		}
+		return database.UserDashboardPreferences{
+			UserID:            g.UserID,
+			HiddenCollections: g.HiddenCollections,
+			CollectionOrder:   g.CollectionOrder,
+			ItemsPerSection:   g.ItemsPerSection,
+			UpdatedAt:         g.UpdatedAt,
+		}, nil
+	}
 	return s.db.GetDashboardPreferences(ctx, database.GetDashboardPreferencesParams{
 		UserID:    pgtype.UUID{Bytes: userID, Valid: true},
 		LibraryID: libraryID,
@@ -383,6 +399,24 @@ func (s *DashboardService) GetDashboardPreferences(ctx context.Context, userID u
 }
 
 func (s *DashboardService) UpsertDashboardPreferences(ctx context.Context, params database.UpsertDashboardPreferencesParams) (database.UserDashboardPreferences, error) {
+	if !params.LibraryID.Valid {
+		g, err := s.db.UpsertGlobalDashboardPreferences(ctx, database.UpsertGlobalDashboardPreferencesParams{
+			UserID:            params.UserID,
+			HiddenCollections: params.HiddenCollections,
+			CollectionOrder:   params.CollectionOrder,
+			ItemsPerSection:   params.ItemsPerSection,
+		})
+		if err != nil {
+			return database.UserDashboardPreferences{}, err
+		}
+		return database.UserDashboardPreferences{
+			UserID:            g.UserID,
+			HiddenCollections: g.HiddenCollections,
+			CollectionOrder:   g.CollectionOrder,
+			ItemsPerSection:   g.ItemsPerSection,
+			UpdatedAt:         g.UpdatedAt,
+		}, nil
+	}
 	return s.db.UpsertDashboardPreferences(ctx, params)
 }