fix: Pi harness - dynamic models, correct RPC protocol, proper event handling

Backend:
- /api/pi/models now calls 'pi --list-models' with stored API keys
- pi-bridge.ts: callback-based event handling (matches pi-monorepo)
- pi-bridge.ts: correct RPC format (type: 'prompt' not jsonrpc)
- pi-bridge.ts: pass API keys to Pi process env
- websocket.ts: event handler runs in background, no blocking
- rest.ts: fix user home path (getHomeDir instead of hardcoded)

Frontend:
- Fix /api/ double prefix in useChatSessions, useChatGroups, useModels
- Add PROVIDER_DISPLAY mapping in SystemSettings.tsx
- Provider tabs show friendly names (e.g., 'OpenCode Zen')

UI (from previous session):
- Grouped session list with collapsible folders
- CreateGroupDialog, GroupContextMenu, SessionContextMenu components

src/apps/officer-web/state/useChatGroups.ts

@@ -11,11 +11,11 @@ export function useChatGroups() {
   const { data: groups = [] } = useQuery<GroupEntry[]>({
     queryKey: ['PI_GROUPS'],
     enabled: isAuthenticated,
-    queryFn: () => client.get<{ groups: GroupEntry[] }>('/api/pi/groups').then((r) => r.groups),
+    queryFn: () => client.get<{ groups: GroupEntry[] }>('/pi/groups').then((r) => r.groups),
   });
 
   async function createGroup(name: string, slug: string, description?: string, sessionIds?: string[]) {
-    const result = await client.post<{ group: GroupEntry }>('/api/pi/groups', {
+    const result = await client.post<{ group: GroupEntry }>('/pi/groups', {
       name,
       slug,
       description,
@@ -27,18 +27,18 @@ export function useChatGroups() {
   }
 
   async function updateGroup(slug: string, updates: { name?: string; description?: string }) {
-    await client.patch(`/api/pi/groups/${slug}`, updates);
+    await client.patch(`/pi/groups/${slug}`, updates);
     queryClient.invalidateQueries({ queryKey: ['PI_GROUPS'] });
   }
 
   async function deleteGroup(slug: string) {
-    await client.delete(`/api/pi/groups/${slug}`);
+    await client.delete(`/pi/groups/${slug}`);
     queryClient.invalidateQueries({ queryKey: ['PI_GROUPS'] });
     queryClient.invalidateQueries({ queryKey: ['PI_SESSIONS'] });
   }
 
   async function moveSession(sessionId: string, groupSlug: string | null) {
-    await client.post(`/api/pi/sessions/${sessionId}/move`, { groupSlug });
+    await client.post(`/pi/sessions/${sessionId}/move`, { groupSlug });
     queryClient.invalidateQueries({ queryKey: ['PI_GROUPS'] });
     queryClient.invalidateQueries({ queryKey: ['PI_SESSIONS'] });
   }

src/apps/officer-web/state/useChatSessions.ts

@@ -28,24 +28,24 @@ export function useChatSessions() {
   const { data: sessions = [] } = useQuery<SessionEntry[]>({
     queryKey: ['PI_SESSIONS'],
     enabled: isAuthenticated,
-    queryFn: () => client.post<{ sessions: SessionEntry[] }>('/api/pi/sessions').then((r) => r.sessions),
+    queryFn: () => client.post<{ sessions: SessionEntry[] }>('/pi/sessions').then((r) => r.sessions),
   });
 
   function getSession(sessionId: string) {
-    return client.get<{ session: SessionWithMessages }>(`/api/pi/sessions/${sessionId}`);
+    return client.get<{ session: SessionWithMessages }>(`/pi/sessions/${sessionId}`);
   }
 
   function saveMessages(sessionId: string, messages: ChatMessage[]) {
-    return client.put(`/api/pi/sessions/${sessionId}/messages`, messages);
+    return client.put(`/pi/sessions/${sessionId}/messages`, messages);
   }
 
   async function renameSession(sessionId: string, title: string) {
-    await client.patch(`/api/pi/sessions/${sessionId}`, { title });
+    await client.patch(`/pi/sessions/${sessionId}`, { title });
     queryClient.invalidateQueries({ queryKey: ['PI_SESSIONS'] });
   }
 
   async function deleteSession(sessionId: string) {
-    await client.delete(`/api/pi/sessions/${sessionId}`);
+    await client.delete(`/pi/sessions/${sessionId}`);
     queryClient.setQueryData<SessionEntry[]>(
       ['PI_SESSIONS'],
       (prev) => prev?.filter((s) => s.id !== sessionId) ?? [],
@@ -53,7 +53,7 @@ export function useChatSessions() {
   }
 
   function searchSessions(query: string) {
-    return client.get<{ results: SessionEntry[] }>(`/api/pi/sessions/search?q=${encodeURIComponent(query)}`);
+    return client.get<{ results: SessionEntry[] }>(`/pi/sessions/search?q=${encodeURIComponent(query)}`);
   }
 
   return {

src/apps/officer-web/state/useModels.ts

@@ -18,7 +18,7 @@ export function usePiModels() {
     queryKey: ['PI_MODELS'],
     enabled: isAuthenticated,
     queryFn: async () => {
-      const data = await client.get<{ models: ModelOption[] }>('/api/pi/models');
+      const data = await client.get<{ models: ModelOption[] }>('/pi/models');
       return data.models;
     },
     staleTime: 5 * 60 * 1000,