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/sessions.ts

@@ -19,6 +19,8 @@ const PatchBody = z.object({
   model: z.string().min(1).max(200).optional(),
   system_prompt: z.string().max(8000).optional(),
   agent_id: z.string().min(1).max(200).nullable().optional(),
+  // v1.9: null = inherit from project default; true/false = explicit override.
+  web_search_enabled: z.boolean().nullable().optional(),
 });
 
 async function resolveDefaultModel(sql: Sql, config: Config): Promise<string> {
@@ -50,7 +52,7 @@ export function registerSessionRoutes(
       }
       const status = req.query.status === 'archived' ? 'archived' : 'open';
       const rows = await sql<Session[]>`
-        SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+        SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id, web_search_enabled
         FROM sessions
         WHERE project_id = ${req.params.id} AND status = ${status}
         ORDER BY updated_at DESC
@@ -100,7 +102,7 @@ export function registerSessionRoutes(
         const [session] = await tx<Session[]>`
           INSERT INTO sessions (project_id, name, model, system_prompt, agent_id)
           VALUES (${req.params.id}, ${name}, ${model}, ${systemPrompt}, ${agentId})
-          RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+          RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id, web_search_enabled
         `;
         await tx`
           INSERT INTO chats (session_id, name, status)
@@ -120,7 +122,7 @@ export function registerSessionRoutes(
 
   app.get<{ Params: { id: string } }>('/api/sessions/:id', async (req, reply) => {
     const rows = await sql<Session[]>`
-      SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+      SELECT id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id, web_search_enabled
       FROM sessions WHERE id = ${req.params.id}
     `;
     if (rows.length === 0) {
@@ -139,10 +141,13 @@ export function registerSessionRoutes(
         return { error: 'invalid body', details: parsed.error.flatten() };
       }
       const { name, model, system_prompt } = parsed.data;
-      // agent_id is tri-state on the wire: omitted = no change, null = clear,
-      // string = set. CASE WHEN inside SET handles all three atomically.
+      // agent_id and web_search_enabled are both tri-state on the wire: omitted
+      // = no change, null = clear/inherit, value = set. CASE WHEN inside SET
+      // handles all three atomically.
       const agentIdProvided = parsed.data.agent_id !== undefined;
       const newAgentId = parsed.data.agent_id ?? null;
+      const wseProvided = parsed.data.web_search_enabled !== undefined;
+      const newWse = parsed.data.web_search_enabled ?? null;
       // Read the prior name so the post-update publish can skip no-op renames
       // (PATCH { name: "Foo" } where the session is already "Foo"). The window
       // between SELECT and UPDATE is sub-millisecond in the same request handler;
@@ -159,9 +164,11 @@ export function registerSessionRoutes(
           model = COALESCE(${model ?? null}, model),
           system_prompt = COALESCE(${system_prompt ?? null}, system_prompt),
           agent_id = CASE WHEN ${agentIdProvided} THEN ${newAgentId} ELSE agent_id END,
+          web_search_enabled = CASE WHEN ${wseProvided} THEN ${newWse} ELSE web_search_enabled END,
           updated_at = clock_timestamp()
         WHERE id = ${req.params.id}
-        RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+        RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at,
+                  agent_id, web_search_enabled
       `;
       if (rows.length === 0) {
         reply.code(404);
@@ -175,10 +182,69 @@ export function registerSessionRoutes(
           name: session.name,
         });
       }
+      // v1.9: any successful PATCH broadcasts session_updated so listeners
+      // (notably the SettingsPane open in another tab) can refetch and pick
+      // up the new fields. Frame stays lean (decision d) — payload is just
+      // ids + name + updated_at, the client refetches via api.sessions.get.
+      broker.publishUser('default', {
+        type: 'session_updated',
+        session_id: session.id,
+        project_id: session.project_id,
+        name: session.name,
+        updated_at: session.updated_at,
+      });
       return session;
     }
   );
 
+  // v1.9: bulk-archive every open session in a project. Mirrors the
+  // single-archive shape (same broker frame type) so the existing useSidebar
+  // reducer cases handle it without changes — just N frames instead of 1.
+  app.post<{ Params: { id: string } }>(
+    '/api/projects/:id/sessions/archive-all',
+    async (req, reply) => {
+      const project = await sql`SELECT id FROM projects WHERE id = ${req.params.id}`;
+      if (project.length === 0) {
+        reply.code(404);
+        return { error: 'project not found' };
+      }
+      const rows = await sql<{ id: string }[]>`
+        UPDATE sessions
+           SET status = 'archived', updated_at = clock_timestamp()
+         WHERE project_id = ${req.params.id} AND status = 'open'
+         RETURNING id
+      `;
+      const ids = rows.map((r) => r.id);
+      for (const id of ids) {
+        broker.publishUser('default', {
+          type: 'session_archived',
+          session_id: id,
+          project_id: req.params.id,
+        });
+      }
+      return { archived: ids.length, ids };
+    }
+  );
+
+  // v1.9: count helper for the confirm dialog. Cheap COUNT(*) — the settings
+  // pane calls it on click, not on render.
+  app.get<{ Params: { id: string } }>(
+    '/api/projects/:id/sessions/open-count',
+    async (req, reply) => {
+      const project = await sql`SELECT id FROM projects WHERE id = ${req.params.id}`;
+      if (project.length === 0) {
+        reply.code(404);
+        return { error: 'project not found' };
+      }
+      const rows = await sql<{ count: number }[]>`
+        SELECT COUNT(*)::int AS count
+          FROM sessions
+         WHERE project_id = ${req.params.id} AND status = 'open'
+      `;
+      return { count: rows[0]?.count ?? 0 };
+    }
+  );
+
   app.post<{ Params: { id: string } }>(
     '/api/sessions/:id/archive',
     async (req, reply) => {
@@ -207,7 +273,7 @@ export function registerSessionRoutes(
       const rows = await sql<Session[]>`
         UPDATE sessions SET status = 'open', updated_at = clock_timestamp()
         WHERE id = ${req.params.id} AND status = 'archived'
-        RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id
+        RETURNING id, project_id, name, model, system_prompt, status, created_at, updated_at, agent_id, web_search_enabled
       `;
       if (rows.length === 0) {
         reply.code(404);