feat(dashboard): collapsible This Week widget, library-scoped + switch-surviving; title into the subbar

Three dashboard complaints, one build:

- The widget collapses to a single summary row (This Week · minutes ·
  pages · sessions · books · streak · Full stats) on every screen size
  and expands to the full grid via a details/summary toggle — the
  carousel sections start immediately below it again.
- The 'Your Library' heading moved into the library switcher subbar
  (LibrarySwitcher gains an optional title param; collections/series
  keep the plain 'Library' label). The standalone heading block is
  gone.
- Root-caused the JS-switch vanishing: renderDashboardCollections
  replaces ALL of #collections-container's innerHTML, so anything
  server-rendered inside it (title, widget) died on the first library
  switch. The widget now re-fetches ITSELF: a /dashboard/week-widget
  fragment (same resolveLibrary family-lens rules as the page) is
  pulled by htmx whenever the switcher dispatches week-refresh —
  carrying the current #library-select value — so the widget both
  survives switches and RE-SCOPES to the switched library. Initial SSR
  renders the same scope the sections use.

ThisWeek (and the streak calendar) gained an optional library filter.
Tests: TestReadingStatsWeekLibraryScope — per-library totals, scoped
streaks, invisible-library isolation, malformed id 400. Full suite
PASS.

internal/database/queries.sql.go

@@ -8665,7 +8665,8 @@ FROM reading_history rh
 JOIN media_items mi ON mi.id = rh.media_item_id
 WHERE rh.user_id = $2
   AND COALESCE(rh.reading_session_end, rh.created_at) >= $3
-  AND ($4::uuid[] IS NULL OR mi.library_id = ANY($4::uuid[]))
+  AND ($4::uuid IS NULL OR mi.library_id = $4::uuid)
+  AND ($5::uuid[] IS NULL OR mi.library_id = ANY($5::uuid[]))
 ORDER BY day ASC
 `
 
@@ -8673,6 +8674,7 @@ type GetUserReadingActiveDaysParams struct {
 	Tz                string             `db:"tz" json:"tz"`
 	UserID            pgtype.UUID        `db:"user_id" json:"user_id"`
 	StartTime         pgtype.Timestamptz `db:"start_time" json:"start_time"`
+	LibraryID         pgtype.UUID        `db:"library_id" json:"library_id"`
 	VisibleLibraryIds []pgtype.UUID      `db:"visible_library_ids" json:"visible_library_ids"`
 }
 
@@ -8685,6 +8687,7 @@ func (q *Queries) GetUserReadingActiveDays(ctx context.Context, arg GetUserReadi
 		arg.Tz,
 		arg.UserID,
 		arg.StartTime,
+		arg.LibraryID,
 		arg.VisibleLibraryIds,
 	)
 	if err != nil {
@@ -8806,7 +8809,8 @@ JOIN media_items mi ON mi.id = rh.media_item_id
 WHERE rh.user_id = $1
   AND COALESCE(rh.reading_session_end, rh.created_at) >= $2
   AND COALESCE(rh.reading_session_end, rh.created_at) <= $3
-  AND ($4::uuid[] IS NULL OR mi.library_id = ANY($4::uuid[]))
+  AND ($4::uuid IS NULL OR mi.library_id = $4::uuid)
+  AND ($5::uuid[] IS NULL OR mi.library_id = ANY($5::uuid[]))
 ORDER BY rh.created_at ASC
 `
 
@@ -8814,6 +8818,7 @@ type GetUserReadingSessionsRangeParams struct {
 	UserID            pgtype.UUID        `db:"user_id" json:"user_id"`
 	StartTime         pgtype.Timestamptz `db:"start_time" json:"start_time"`
 	EndTime           pgtype.Timestamptz `db:"end_time" json:"end_time"`
+	LibraryID         pgtype.UUID        `db:"library_id" json:"library_id"`
 	VisibleLibraryIds []pgtype.UUID      `db:"visible_library_ids" json:"visible_library_ids"`
 }
 
@@ -8846,6 +8851,7 @@ func (q *Queries) GetUserReadingSessionsRange(ctx context.Context, arg GetUserRe
 		arg.UserID,
 		arg.StartTime,
 		arg.EndTime,
+		arg.LibraryID,
 		arg.VisibleLibraryIds,
 	)
 	if err != nil {

internal/database/queries/queries.sql

@@ -1486,6 +1486,7 @@ JOIN media_items mi ON mi.id = rh.media_item_id
 WHERE rh.user_id = sqlc.arg('user_id')
   AND COALESCE(rh.reading_session_end, rh.created_at) >= sqlc.arg('start_time')
   AND COALESCE(rh.reading_session_end, rh.created_at) <= sqlc.arg('end_time')
+  AND (sqlc.narg('library_id')::uuid IS NULL OR mi.library_id = sqlc.narg('library_id')::uuid)
   AND (sqlc.narg('visible_library_ids')::uuid[] IS NULL OR mi.library_id = ANY(sqlc.narg('visible_library_ids')::uuid[]))
 ORDER BY rh.created_at ASC;
 
@@ -1551,6 +1552,7 @@ FROM reading_history rh
 JOIN media_items mi ON mi.id = rh.media_item_id
 WHERE rh.user_id = sqlc.arg('user_id')
   AND COALESCE(rh.reading_session_end, rh.created_at) >= sqlc.arg('start_time')
+  AND (sqlc.narg('library_id')::uuid IS NULL OR mi.library_id = sqlc.narg('library_id')::uuid)
   AND (sqlc.narg('visible_library_ids')::uuid[] IS NULL OR mi.library_id = ANY(sqlc.narg('visible_library_ids')::uuid[]))
 ORDER BY day ASC;
 

internal/handlers/stats.go

@@ -50,14 +50,25 @@ func (h *StatsHandler) Summary(c *echo.Context) error {
 
 // ThisWeek handles GET /api/stats/this-week — the dashboard widget's
 // data: rolling 7-day totals vs the previous seven days, plus streak.
+// An optional ?library_id scopes the week to one library (the
+// dashboard's library switcher drives it).
 func (h *StatsHandler) ThisWeek(c *echo.Context) error {
 	user, ok := mustUser(c)
 	if !ok {
 		return echo.NewHTTPError(http.StatusUnauthorized, "invalid user")
 	}
+	var libraryID pgtype.UUID
+	if raw := c.QueryParam("library_id"); raw != "" {
+		parsed, err := uuid.Parse(raw)
+		if err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest, "invalid library id")
+		}
+		libraryID = pgtype.UUID{Bytes: parsed, Valid: true}
+	}
 	week, err := h.statsService.ThisWeek(c.Request().Context(),
 		pgtype.UUID{Bytes: user.ID.Bytes, Valid: true},
 		user.Timezone.String,
+		libraryID,
 	)
 	if err != nil {
 		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())

internal/router/frontend.go

@@ -473,13 +473,18 @@ func registerFrontendRoutes(cfg *Config) {
 		sectionData := handlers.MarkActiveConflictsSections(c.Request().Context(), cfg.Queries, userPgID, handlers.BuildSections(visibleSections, libraryID))
 		allSectionsData := handlers.BuildSections(allSections, libraryID)
 
-		// “This week” widget: the user's rolling 7-day reading pulse, from
-		// the same session seed the /stats page uses. Suppressed when the
-		// service fails (dashboard always renders).
+		// "This week" widget: the user's rolling 7-day reading pulse for
+		// the CURRENTLY SELECTED library (the same resolution the sections
+		// use), from the same session seed the /stats page serves.
+		// Suppressed when the service fails (dashboard always renders).
 		var week *templates.WeekStatsData
 		if cfg.StatisticsService != nil {
+			weekScope := pgtype.UUID{}
+			if !libRes.IsAll {
+				weekScope = libRes.LibUUID
+			}
 			weekSvc, weekErr := cfg.StatisticsService.ThisWeek(c.Request().Context(),
-				pgtype.UUID{Bytes: userUUID, Valid: true}, user.Timezone)
+				pgtype.UUID{Bytes: userUUID, Valid: true}, user.Timezone, weekScope)
 			if weekErr == nil {
 				week = &templates.WeekStatsData{
 					WeekMinutes:   weekSvc.WeekMinutes,
@@ -489,6 +494,7 @@ func registerFrontendRoutes(cfg *Config) {
 					PrevMinutes:   weekSvc.PrevMinutes,
 					ActiveToday:   weekSvc.ActiveToday,
 					CurrentStreak: weekSvc.CurrentStreak,
+					LibraryID:     libRes.LibraryID,
 				}
 			} else {
 				log.Printf("ThisWeek widget failed: %v", weekErr)
@@ -840,6 +846,46 @@ func registerFrontendRoutes(cfg *Config) {
 		return c.HTML(http.StatusOK, buf.String())
 	})
 
+	// Week-widget fragment: the collapsible "This Week" strip re-fetches
+	// itself here (htmx) whenever the library switcher dispatches
+	// week-refresh, carrying the current #library-select value. Same
+	// resolution rules as the dashboard page (family-lens safe).
+	frontendProtected.GET("/dashboard/week-widget", func(c *echo.Context) error {
+		user, err := getTemplateUserWithTheme(c, cfg)
+		if err != nil {
+			return echo.NewHTTPError(http.StatusUnauthorized, "invalid user")
+		}
+		if cfg.StatisticsService == nil {
+			return echo.NewHTTPError(http.StatusServiceUnavailable, "stats unavailable")
+		}
+		libRes := resolveLibrary(c, cfg, user.ID)
+		weekScope := pgtype.UUID{}
+		if !libRes.IsAll {
+			weekScope = libRes.LibUUID
+		}
+		userUUID, _ := uuid.Parse(user.ID)
+		weekSvc, weekErr := cfg.StatisticsService.ThisWeek(c.Request().Context(),
+			uuidToPGType(userUUID), user.Timezone, weekScope)
+		if weekErr != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, weekErr.Error())
+		}
+		var buf bytes.Buffer
+		err = templates.DashboardWeekWidget(templates.WeekStatsData{
+			WeekMinutes:   weekSvc.WeekMinutes,
+			WeekPages:     weekSvc.WeekPages,
+			WeekSessions:  weekSvc.WeekSessions,
+			WeekBooks:     weekSvc.WeekBooks,
+			PrevMinutes:   weekSvc.PrevMinutes,
+			ActiveToday:   weekSvc.ActiveToday,
+			CurrentStreak: weekSvc.CurrentStreak,
+			LibraryID:     libRes.LibraryID,
+		}).Render(c.Request().Context(), &buf)
+		if err != nil {
+			return err
+		}
+		return c.HTML(http.StatusOK, buf.String())
+	})
+
 	// Custom Section Builder page
 	frontendProtected.GET("/custom-section", func(c *echo.Context) error {
 		user, err := getTemplateUserWithTheme(c, cfg)

internal/services/statistics_service.go

@@ -431,8 +431,10 @@ func (s *StatisticsService) UserSummary(ctx context.Context, userID pgtype.UUID,
 
 // ThisWeek builds the dashboard widget: the current rolling 7-day
 // window (today inclusive) versus the previous seven days, plus the
-// streak context. One scan over 14 days, split in Go.
-func (s *StatisticsService) ThisWeek(ctx context.Context, userID pgtype.UUID, tz string) (WeekSummaryStats, error) {
+// streak context. One scan over 14 days, split in Go. libraryID scopes
+// everything to one library (invalid = all visible libraries) so the
+// widget tracks the dashboard's library switcher.
+func (s *StatisticsService) ThisWeek(ctx context.Context, userID pgtype.UUID, tz string, libraryID pgtype.UUID) (WeekSummaryStats, error) {
 	statsRange, err := ResolveStatsRange(tz, "7")
 	if err != nil {
 		return WeekSummaryStats{}, err
@@ -450,6 +452,7 @@ func (s *StatisticsService) ThisWeek(ctx context.Context, userID pgtype.UUID, tz
 		UserID:            userID,
 		StartTime:         pgtype.Timestamptz{Time: scanStart, Valid: true},
 		EndTime:           pgtype.Timestamptz{Time: statsRange.End, Valid: true},
+		LibraryID:         libraryID,
 		VisibleLibraryIds: visibleOrNil(visibleIDs),
 	})
 	if err != nil {
@@ -511,6 +514,7 @@ func (s *StatisticsService) ThisWeek(ctx context.Context, userID pgtype.UUID, tz
 		Tz:                loc.String(),
 		UserID:            userID,
 		StartTime:         pgtype.Timestamptz{Time: statsRange.Start.AddDate(0, 0, -(streakLookbackDays - statsRange.Days)), Valid: true},
+		LibraryID:         libraryID,
 		VisibleLibraryIds: visibleOrNil(visibleIDs),
 	})
 	if err == nil {