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/queries/queries.sql

@@ -2190,6 +2190,11 @@ SET
 WHERE id = $1
 RETURNING *;
 
+-- Replace ONLY the auto_assign_rules document (rule CRUD: read-modify-write
+-- of the JSONB without touching metadata stale clients did not send).
+-- name: UpdateCollectionRulesJSON :one
+UPDATE collections SET auto_assign_rules = $2 WHERE id = $1 RETURNING *;
+
 -- Delete collection
 -- name: DeleteCollection :exec
 DELETE FROM collections WHERE id = $1;
@@ -2628,6 +2633,31 @@ WHERE ci.collection_id = sqlc.narg('collection_id')
 ORDER BY ci.added_at DESC
 LIMIT sqlc.narg('limit');
 
+-- 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.
+-- name: GetVisibleLiveMediaForRules :many
+SELECT mi.* FROM media_items mi
+WHERE (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[]))
+  AND mi.archived_at IS NULL
+  AND mi.missing_scan_count = 0
+ORDER BY mi.title ASC;
+
+-- 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.
+-- name: CountCollectionLiveItems :one
+SELECT COUNT(*)::int FROM collection_items ci
+JOIN media_items mi ON ci.media_item_id = mi.id
+WHERE ci.collection_id = $1
+  AND NOT COALESCE(ci.excluded, false)
+  AND (sqlc.narg('library_id')::uuid IS NULL OR mi.library_id = sqlc.narg('library_id')::uuid)
+  AND mi.archived_at IS NULL
+  AND mi.missing_scan_count = 0;
+
 -- name: GetLibraryItems :many
 SELECT mi.* FROM media_items mi
 WHERE (sqlc.narg('library_id')::uuid IS NULL OR mi.library_id = sqlc.narg('library_id')::uuid)