feat(collections): smart (dynamic) collections — rules evaluated live at render

Type is DERIVED, not stored: a saved ruleset makes a collection SMART,
no rules = STATIC (stored collection_items links, unchanged behavior).
No schema change — collections.auto_assign_rules JSONB already carried
the config; user's decision 2026-10-14 (handoff: live-at-render, not
refresh-on-scan; create-time Static/Smart toggle; v1 NO hybrid).

- Rule gains an enabled flag (absent = enabled, legacy rules unaffected).
- Rule CRUD: POST/PUT(DELETE) /api/collections/:id/rules[/:ruleId] — the
  survivor dead effort of the rules-builder UI finally has real
  endpoints (rules were never editable after creation; nothing ever
  re-evaluated them). First rule converts a user collection to smart;
  removing the last reverts it to static. UpdateCollectionRulesJSON
  edits ONLY the rules doc so rule CRUD cannot clobber metadata.
- Live evaluation: candidates from GetVisibleLiveMediaForRules —
  visible-library set (family lens enforced at source) + archived IS
  NULL AND missing_scan_count = 0 — any enabled rule matches, title
  order. Zero refresh hooks by design: always current by construction.
- Membership mutations (add/remove/bulk-add) are 400 on smart — v1 no
  hybrid; collection_items.excluded stays the reserved future hook.
- Rules builder page (/collections/:id/rules) first time ever routable;
  templ whole-attribute interpolation ("{ expr }" inside a quoted attr
  value is literal text, as theme-{ user.Theme } silently proved).
- UI: create modal Static/⚡Smart cards (smart create redirects into the
  rules builder), ⚡ badge + real per-card counts on the grid (smart =
  live matches, static = stored-link count), smart detail renders
  matched books with no hand-pick actions + an Edit Rules button.
- API: GET /:id gains is_smart + live books; GET /: keeps the Android
  app's default exclusion, include_auto=true surfaces smart rows with
  live counts; TestRules previews against the SAME candidates the live
  render uses (visible + live, was raw first-1000).
- FIXED pre-existing regression from 7ce7321: static collection detail
  with NO library_id returned zero books — QueryType != '' caught user
  rows ('filter' default) and routed them to dashboard sections that
  never contain them; now only real system query types go there
  (handlers + SSR). App-visible symptom: /api/collections/:id without
  library_id came back books:[] for every static collection.

Tests: collections_smart_test.go (conversion, disabled rules, mutation
guards, revert-to-static, validation, system-collection prohibition,
include_auto semantics). Full offline integration suite PASS.

internal/database/querier.go

@@ -42,6 +42,10 @@ type Querier interface {
 	ClearMediaItemMetadataOverrides(ctx context.Context, id pgtype.UUID) error
 	CountAdmins(ctx context.Context) (int64, error)
 	CountArchivedMediaItems(ctx context.Context) (int64, error)
+	// Live item count for a STATIC collection (rule-free cards on the
+	// collections page); same live filter as GetCollectionItems, plus the
+	// future-hybrid excluded exclusion and an optional library scope.
+	CountCollectionLiveItems(ctx context.Context, arg CountCollectionLiveItemsParams) (int32, error)
 	// Count unlinked books for a device
 	CountUnlinkedBooks(ctx context.Context, deviceID pgtype.UUID) (int64, error)
 	CountUserDevices(ctx context.Context, userID pgtype.UUID) (int64, error)
@@ -358,6 +362,12 @@ type Querier interface {
 	GetUserReadingHistory(ctx context.Context, arg GetUserReadingHistoryParams) ([]GetUserReadingHistoryRow, error)
 	GetUserVisibleLibraries(ctx context.Context, userID pgtype.UUID) ([]GetUserVisibleLibrariesRow, error)
 	GetVisibleLibraryMediaCounts(ctx context.Context, userID pgtype.UUID) ([]GetVisibleLibraryMediaCountsRow, error)
+	// Smart ("dynamic") collections: rules are evaluated LIVE at render, so
+	// membership comes from the candidate book set instead of collection_items.
+	// The set is scoped to the requesting user's visible libraries (family
+	// lens enforced at the source) and live items only — the same filters the
+	// static collection paths apply.
+	GetVisibleLiveMediaForRules(ctx context.Context, arg GetVisibleLiveMediaForRulesParams) ([]MediaItems, error)
 	HasRecentConflictResolution(ctx context.Context, arg HasRecentConflictResolutionParams) (bool, error)
 	IncrementSyncQueueAttempts(ctx context.Context, arg IncrementSyncQueueAttemptsParams) (SyncQueue, error)
 	// Check if book is in collection
@@ -474,6 +484,9 @@ type Querier interface {
 	TombstoneSystemCollection(ctx context.Context, id pgtype.UUID) error
 	// Update collection
 	UpdateCollection(ctx context.Context, arg UpdateCollectionParams) (Collections, error)
+	// Replace ONLY the auto_assign_rules document (rule CRUD: read-modify-write
+	// of the JSONB without touching metadata stale clients did not send).
+	UpdateCollectionRulesJSON(ctx context.Context, arg UpdateCollectionRulesJSONParams) (Collections, error)
 	UpdateDashboardPreferences(ctx context.Context, arg UpdateDashboardPreferencesParams) (UserDashboardPreferences, error)
 	UpdateDevice(ctx context.Context, arg UpdateDeviceParams) (Devices, error)
 	UpdateDeviceAuthToken(ctx context.Context, arg UpdateDeviceAuthTokenParams) (Devices, error)