fix(ai): store chatContextWindow as a JSON number, not a ::text string

chatContextWindow (#189) is the first numeric provider field routed
through WorkspaceRepo.updateAiProviderSettings, whose patch builder cast
every value as `${v}::text`. The DTO validates it as @IsInt(), so a JS
number 200000 was stored as the JSON STRING "200000". The client guards
require `typeof === "number"` (ai-chat-window.tsx, context-badge.tsx),
so the `/ max` badge denominator never rendered and the whole feature
silently no-opped.

Branch the jsonb_build_object value cast by JS runtime type: numbers ->
::numeric (real JSON number), booleans -> ::boolean, everything else ->
::text (unchanged for the existing string fields). This is the root fix
(store as a real number) rather than coercing on read, so every reader
sees the correct type.

Add a DB round-trip int-spec asserting
jsonb_typeof(settings->'ai'->'provider'->'chatContextWindow') = 'number'
and that the value re-reads as the number 200000, including the
partial-merge path. CHANGELOG: Added entry for the chatContextWindow
setting and a Changed entry for the badge's new "used / max" meaning.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/server/test/integration/workspace-repo-ai-provider-settings.int-spec.ts

@@ -0,0 +1,91 @@
+import { Kysely, sql } from 'kysely';
+import { WorkspaceRepo } from '@docmost/db/repos/workspace/workspace.repo';
+import { getTestDb, destroyTestDb, createWorkspace } from './db';
+
+/**
+ * WorkspaceRepo.updateAiProviderSettings numeric round-trip (#189, #213).
+ *
+ * `chatContextWindow` is the first NUMERIC provider field routed through this
+ * generic SQL layer. The patch builder must cast a JS number so it lands in
+ * jsonb as a JSON NUMBER, not the JSON STRING `"200000"` — the client guards
+ * (`typeof === "number"`) reject a string, silently killing the `/ max` badge
+ * denominator. A plain `::text` cast (the prior code) regressed exactly this.
+ * These specs are real SQL and assert both the JS value type and the on-disk
+ * `jsonb_typeof`.
+ */
+describe('WorkspaceRepo.updateAiProviderSettings (numeric round-trip) [integration]', () => {
+  let db: Kysely<any>;
+  let repo: WorkspaceRepo;
+
+  beforeAll(() => {
+    db = getTestDb();
+    repo = new WorkspaceRepo(db as any);
+  });
+
+  afterAll(async () => {
+    await destroyTestDb();
+  });
+
+  it('stores chatContextWindow as a JSON number (not a "200000" string)', async () => {
+    const ws = await createWorkspace(db, { settings: undefined });
+
+    const updated = await repo.updateAiProviderSettings(ws.id, {
+      driver: 'openai',
+      chatModel: 'gpt-4o',
+      chatContextWindow: 200000,
+    });
+
+    // Returned row: the number survives as a real JS number, alongside the
+    // string fields which stay strings.
+    const provider = (updated.settings as any)?.ai?.provider;
+    expect(provider.chatContextWindow).toBe(200000);
+    expect(typeof provider.chatContextWindow).toBe('number');
+    expect(provider.driver).toBe('openai');
+    expect(provider.chatModel).toBe('gpt-4o');
+
+    // On disk: the jsonb value is typed 'number' (the must-fix assertion), and
+    // sibling string fields are typed 'string'.
+    const typed = await db
+      .selectFrom('workspaces')
+      .select([
+        sql<string>`jsonb_typeof(settings->'ai'->'provider'->'chatContextWindow')`.as(
+          'windowType',
+        ),
+        sql<string>`jsonb_typeof(settings->'ai'->'provider'->'chatModel')`.as(
+          'modelType',
+        ),
+      ])
+      .where('id', '=', ws.id)
+      .executeTakeFirstOrThrow();
+
+    expect(typed.windowType).toBe('number');
+    expect(typed.modelType).toBe('string');
+  });
+
+  it('re-reads chatContextWindow as a number after a partial-merge update', async () => {
+    const ws = await createWorkspace(db, {
+      settings: { ai: { provider: { driver: 'openai', chatModel: 'x' } } },
+    });
+
+    // Merge in only the numeric field; siblings must be preserved and the value
+    // must still be a JSON number, not a string.
+    await repo.updateAiProviderSettings(ws.id, { chatContextWindow: 128000 });
+
+    const row = await db
+      .selectFrom('workspaces')
+      .select([
+        'settings',
+        sql<string>`jsonb_typeof(settings->'ai'->'provider'->'chatContextWindow')`.as(
+          'windowType',
+        ),
+      ])
+      .where('id', '=', ws.id)
+      .executeTakeFirstOrThrow();
+
+    expect(row.windowType).toBe('number');
+    const provider = (row.settings as any)?.ai?.provider;
+    expect(provider.chatContextWindow).toBe(128000);
+    expect(provider.driver).toBe('openai');
+    expect(provider.chatModel).toBe('x');
+  });
+});