Chat mode, phase 1: grounded streaming chat over your notes

Entry points (no sixth tab): Ask in the Library header (desktop button,
phone icon), Ask about this deck in the deck menu, Ask a question on
study/homework results (compact result travels as context), and a Chat
row in the desktop sidebar. Phones get a full-screen route with back +
New chat; the tab bar steps aside.

- Client-side retrieval: chunk scoped decks (~800 tokens), BM25 against
  the question + recent turns, top chunks under ~7k tokens, each
  labelled with deck + section. Notes come from the deck's stored
  sourceText (already kept for Regenerate); decks without it fall back
  to generated content and the UI says so.
- Stateless server: /api/chat validates against the CHAT_MODELS
  allowlist, trims the history to ~6k tokens, caps context at ~9k and
  streams token/thinking/done/error NDJSON. /api/chat/extract reduces
  attachments to text through the existing vision step.
- UI: user bubbles + full-width assistant text, streaming with stop,
  auto-scroll that pauses with a jump-to-bottom button, safe markdown
  (React nodes, no HTML injection; KaTeX dynamically imported only when
  a message has math), Thinking row for reasoning, copy/regenerate/
  edit-and-resend, model + context pickers (last model remembered),
  composer with visualViewport keyboard handling, safe-area, 16px
  textarea, Enter-to-send on desktop.
- Usage-limit failures keep the draft and show the shared message with
  Settings/Ollama actions; stopping maps the reader abort to a clean
  stopped state; offline disables sending with a reason.
- Settings: Keep notes text for chat toggle; deck menu: Delete notes
  text. RATE_LIMIT_CHAT + CHAT_MODELS in .env.example and README.
- Tests: chat suite (63 checks, stub Ollama) wired into run-all.
  Full set: 12/12 suites, 487 checks. SW -> freezmo-v32.

Also: tests/model-compare.mjs (diagnostic) benchmarks two models on the
same notes (latency, repair rounds, activity types) so the gpt-oss vs
gemma default can be decided on numbers; defaults unchanged.

app/api/health/route.ts

@@ -14,6 +14,12 @@ export type ModelHealth = {
   note?: string;
 };
 
+export type ChatModelHealth = {
+  name: string;
+  badge: "text" | "vision" | "both";
+  available: boolean | null;
+};
+
 export type HealthResponse = {
   ok: boolean;
   reachable: boolean;
@@ -27,6 +33,8 @@ export type HealthResponse = {
   hasApiKey: boolean;
   vision: ModelHealth;
   text: ModelHealth;
+  /** The chat model allowlist (CHAT_MODELS) with availability from the list. */
+  chatModels: ChatModelHealth[];
   latencyMs: number | null;
   modelCount: number | null;
   error: string | null;
@@ -44,6 +52,15 @@ export async function GET(request: Request) {
   const started = Date.now();
   const resolvedAuth = resolveAuth(config, request);
 
+  const badgeFor = (name: string): ChatModelHealth["badge"] => {
+    const canonical = canonicalModelName(name);
+    const isText = canonical === canonicalModelName(config.textModel);
+    const isVision = canonical === canonicalModelName(config.visionModel);
+    if (isText && isVision) return "both";
+    if (isVision) return "vision";
+    return "text";
+  };
+
   const health: HealthResponse = {
     ok: false,
     reachable: false,
@@ -63,6 +80,7 @@ export async function GET(request: Request) {
       resolved: resolveModelName(config.textModel, config.directCloud),
       available: null,
     },
+    chatModels: config.chatModels.map((name) => ({ name, badge: badgeFor(name), available: null })),
     latencyMs: null,
     modelCount: null,
     error: null,
@@ -121,6 +139,9 @@ export async function GET(request: Request) {
             : translate(locale, "server.healthModelNoteCloud", { url: config.baseUrl });
       }
     }
+    for (const entry of health.chatModels) {
+      entry.available = names.has(canonicalModelName(entry.name));
+    }
 
     health.ok = Boolean(health.vision.available && health.text.available && health.keyAccepted !== false);
     if (!health.ok && !health.error) {