v1.9: settings pane + per-project defaults + bulk archive + themes lift

Adds a singleton, ephemeral 'settings' pane kind to the workspace.
Opened via a new bottom-pinned button in ProjectSidebar (emits an
open_settings_pane event when a session is mounted; navigates to
/settings otherwise). Pane has three sections — Session, Project,
Theme — and a maximize toggle that hides sibling pane columns via
display:none on desktop only. Settings panes don't count toward
MAX_PANES and are filtered out of the localStorage persistence layer
so reload always restores a clean workspace.

Schema (additive):
- projects.default_system_prompt TEXT NOT NULL DEFAULT ''
- projects.default_web_search_enabled BOOLEAN NOT NULL DEFAULT false
- sessions.web_search_enabled BOOLEAN  (nullable; null = inherit)

Inference resolves user_prompt = session.system_prompt.trim() ||
project.default_system_prompt.trim() — empty/whitespace at either
layer means "no override". Keeps the columns NOT NULL and matches
the existing inherit semantics.

Server routes:
- GET /api/projects/:id (new; settings pane refetches on
  project_updated)
- PATCH /api/projects/:id accepts default_system_prompt,
  default_web_search_enabled
- PATCH /api/sessions/:id accepts web_search_enabled (tri-state)
- POST /api/projects/:id/sessions/archive-all + GET
  /api/projects/:id/sessions/open-count
- POST /api/sessions/:id/chats/archive-all + GET
  /api/sessions/:id/chats/open-count
- PATCH /api/sessions/:id now broadcasts session_updated on every
  successful PATCH (was rename-only). Lets SettingsPane open in
  another tab pick up edits without a refetch.

Bulk-archive publishes one session_archived / chat_archived frame
per affected id so useSidebar's existing reducer cases handle them
incrementally — no new frame type, no payload widening.

ModelPicker refactored: shared ModelList inside a responsive shell.
Desktop = labeled trigger + DropdownMenu, mobile = icon-only Cpu
button + BottomSheet. Header in Session.tsx drops the pill wrap on
mobile since the new trigger is the visual.

ChatInput gains an icon-only '+' DropdownMenu next to AgentPicker
when sessionId + webSearchEnabled props are provided. One item for
now — Web search — with a checkmark reflecting the stored value
(true), not the effective one. Click PATCHes the override; to
restore inherit-from-project the user opens SettingsPane.

ThemePicker lifted out of pages/Settings.tsx into a reusable
component. The standalone /settings route is now a thin wrapper
that mounts <ThemePicker /> with a Back button on top
(navigate(-1) with fallback to '/'); the SettingsPane Theme tab
renders the same picker bare.

Project section delete-flow removed (button + confirm dialog +
handler). Replaced with "Archive all sessions" using the same
two-step count → confirm → fire pattern as "Archive all chats" in
the Session section. api.projects.remove() stays in the client
because useProjects.ts still uses it.

Hand-rolled Switch primitive in SettingsPane (no shadcn switch in
the project; spec said no new deps). Section nav is plain buttons
(no shadcn Tabs).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/routes/projects.ts

@@ -22,8 +22,14 @@ const AddProjectBody = z.object({
   name: z.string().min(1).optional(),
 });
 
+// v1.9: PATCH accepts the new per-project defaults. All fields optional so
+// the existing rename-only callers keep working. Empty string on
+// default_system_prompt is the "no override" sentinel — same convention as
+// sessions.system_prompt.
 const PatchProjectBody = z.object({
-  name: z.string().min(1).max(200),
+  name: z.string().min(1).max(200).optional(),
+  default_system_prompt: z.string().max(8000).optional(),
+  default_web_search_enabled: z.boolean().optional(),
 });
 
 const CreateProjectBody = z.object({
@@ -70,7 +76,8 @@ export function registerProjectRoutes(
   app.get<{ Querystring: { status?: string } }>('/api/projects', async (req) => {
     const status = req.query.status === 'archived' ? 'archived' : 'open';
     const rows = await sql<Project[]>`
-      SELECT id, name, path, added_at, last_session_id, status, gitea_remote
+      SELECT id, name, path, added_at, last_session_id, status, gitea_remote,
+             default_system_prompt, default_web_search_enabled
       FROM projects
       WHERE status = ${status}
       ORDER BY added_at DESC
@@ -119,7 +126,8 @@ export function registerProjectRoutes(
       const [row] = await sql<Project[]>`
         INSERT INTO projects (name, path, gitea_remote)
         VALUES (${parsed.data.name}, ${bootstrap.folder_real_path}, ${bootstrap.gitea_remote_url})
-        RETURNING id, name, path, added_at, last_session_id, status, gitea_remote
+        RETURNING id, name, path, added_at, last_session_id, status, gitea_remote,
+                  default_system_prompt, default_web_search_enabled
       `;
       broker.publishUser('default', { type: 'project_created', project: row as unknown as Project });
       reply.code(201);
@@ -173,7 +181,8 @@ export function registerProjectRoutes(
       INSERT INTO projects (name, path)
       VALUES (${name}, ${resolved.real})
       ON CONFLICT (path) DO UPDATE SET status = 'open'
-      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote
+      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote,
+                default_system_prompt, default_web_search_enabled
     `;
 
     if (existing.length === 0) {
@@ -187,22 +196,53 @@ export function registerProjectRoutes(
     return row;
   });
 
+  // v1.9: single-project fetch so the settings pane can refetch on
+  // project_updated without pulling the whole project list.
+  app.get<{ Params: { id: string } }>('/api/projects/:id', async (req, reply) => {
+    const rows = await sql<Project[]>`
+      SELECT id, name, path, added_at, last_session_id, status, gitea_remote,
+             default_system_prompt, default_web_search_enabled
+      FROM projects WHERE id = ${req.params.id}
+    `;
+    if (rows.length === 0) {
+      reply.code(404);
+      return { error: 'not found' };
+    }
+    return rows[0];
+  });
+
   app.patch<{ Params: { id: string } }>('/api/projects/:id', async (req, reply) => {
     const parsed = PatchProjectBody.safeParse(req.body);
     if (!parsed.success) {
       reply.code(400);
       return { error: 'invalid body', details: parsed.error.flatten() };
     }
+    const { name, default_system_prompt, default_web_search_enabled } = parsed.data;
+    // v1.9: every field optional. COALESCE on the bind keeps the prior value
+    // when the caller omits it. Boolean has its own branch since COALESCE
+    // can't disambiguate "omitted" from "explicitly false" via a single
+    // nullable parameter.
+    const dwsProvided = default_web_search_enabled !== undefined;
     const rows = await sql<Project[]>`
-      UPDATE projects SET name = ${parsed.data.name}
+      UPDATE projects
+      SET
+        name = COALESCE(${name ?? null}, name),
+        default_system_prompt = COALESCE(${default_system_prompt ?? null}, default_system_prompt),
+        default_web_search_enabled = CASE WHEN ${dwsProvided}
+          THEN ${default_web_search_enabled ?? false}
+          ELSE default_web_search_enabled END
       WHERE id = ${req.params.id}
-      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote
+      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote,
+                default_system_prompt, default_web_search_enabled
     `;
     if (rows.length === 0) {
       reply.code(404);
       return { error: 'not found' };
     }
     const project = rows[0]!;
+    // v1.9: the project_updated frame still only carries id + name. Clients
+    // that need the new fields refetch via api.projects.list() — keeps the
+    // frame payload lean, per the locked recon decision (d).
     broker.publishUser('default', {
       type: 'project_updated',
       project_id: project.id,
@@ -229,7 +269,8 @@ export function registerProjectRoutes(
     const rows = await sql<Project[]>`
       UPDATE projects SET status = 'open'
       WHERE id = ${req.params.id} AND status = 'archived'
-      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote
+      RETURNING id, name, path, added_at, last_session_id, status, gitea_remote,
+                default_system_prompt, default_web_search_enabled
     `;
     if (rows.length === 0) {
       reply.code(404);