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.

templates/collection_rules.templ

@@ -11,7 +11,7 @@ templ CollectionRules(user User, collection CollectionData) {
 			<link href="/static/style.css" rel="stylesheet"/>
 			<link rel="icon" type="image/svg+xml" href="/static/favicon.svg"/>
 		</head>
-		<body class="theme-{ user.Theme }" x-data="collectionRules" x-init="initCollectionRules('{ collection.ID }')">
+		<body class="theme-{ user.Theme }" x-data="collectionRules" x-init={ "initCollectionRules('" + collection.ID + "')" }>
 			@Header(user, "/collections")
 			<div class="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-8">
 				<div class="mb-6">
@@ -23,19 +23,23 @@ templ CollectionRules(user User, collection CollectionData) {
 						<span class="grid place-items-center h-12 w-12 rounded-2xl shrink-0 text-2xl" style="background-color: var(--accent-muted); color: { collection.Color }">{ collection.Icon }</span>
 						<div>
 							<h1 class="text-3xl font-bold" style="color: var(--text-primary)">{ collection.Name }</h1>
-							<p style="color: var(--text-secondary)">Auto-Assign Rules</p>
+							<p class="flex items-center gap-2" style="color: var(--text-secondary)">
+								<span class="badge text-xs" style="background-color: var(--accent-muted); color: var(--accent);">⚡ Smart</span>
+								Rules evaluated live — the collection is always current, no refresh needed
+							</p>
 						</div>
 					</div>
 				</div>
 				<div class="mb-8">
-					<h2 class="text-2xl font-bold mb-4" style="color: var(--text-primary)">Existing Rules</h2>
+					<h2 class="text-2xl font-bold mb-4" style="color: var(--text-primary)">Rules</h2>
+					<p class="text-sm mb-4" style="color: var(--text-secondary)">A book is in the collection while it matches ANY enabled rule. Saving here takes effect immediately, everywhere the collection renders.</p>
 					<div id="rules-container" class="space-y-4">
 						<div id="no-rules" class="card p-8 text-center">
 							<span class="inline-grid place-items-center h-12 w-12 rounded-xl mb-3" style="background-color: var(--accent-muted); color: var(--accent);">
 								@Icon("filter", "h-6 w-6")
 							</span>
 							<h3 class="text-lg font-semibold mb-2" style="color: var(--text-primary)">No Rules Yet</h3>
-							<p style="color: var(--text-secondary)">Create auto-assign rules to automatically add books to this collection</p>
+							<p style="color: var(--text-secondary)">Add a rule to make this collection smart — it will then match the rule live, everywhere. Removing the last rule makes it static again.</p>
 						</div>
 					</div>
 				</div>