fix(pi): add snap node compatibility diagnostics and documentation

- Added detailed error logging to detect snap node compatibility issues
- When Pi process exits with code 1, log helpful diagnostic info including node path
- Add hint to check for snap node and reinstall via apt/nvm
- Create SNAP_NODE_COMPATIBILITY.md with full troubleshooting guide
- Document root cause: snap node has file descriptor incompatibility with Bun.spawn stdin pipes
- Provide clear installation instructions for NodeSource and nvm alternatives

src/servers/api/pi/rest.ts

@@ -30,6 +30,7 @@ piRestRouter.get('/pi/models', async (ctx: Context) => {
       providerNames[`officer-local-${lp.id}`] = lp.name;
     }
 
+    logger.info('Models endpoint', { count: models.length, providers: [...new Set(models.map((m) => m.provider))] });
     return ctx.json({ models, providerNames, hostHome: process.env.HOME ?? '' });
   } catch (err) {
     logger.error('Failed to list models', { error: String(err) });
@@ -51,7 +52,9 @@ piRestRouter.post('/pi/sessions', async (ctx: Context) => {
   const body = await ctx.req.json().catch(() => ({}));
   const userHome = getHomeDir(user.email);
   const filterCwd = body.cwd ? resolveBaseCwd(user.email, body.cwdRoot, body.cwd) : null;
-  const contextFilter = body.context ? { context: body.context as string, contextId: body.contextId as string | undefined } : undefined;
+  const contextFilter = body.context
+    ? { context: body.context as string, contextId: body.contextId as string | undefined }
+    : undefined;
 
   try {
     let sessions = await storage.listUserSessions(userHome, contextFilter);
@@ -119,6 +122,14 @@ piRestRouter.get('/pi/sessions/:sessionId', async (ctx: Context) => {
   }
 });
 
+/**
+ * PUT /api/pi/sessions/:sessionId/messages
+ * Client-side message save — no-op, sessions are persisted server-side via WebSocket events
+ */
+piRestRouter.put('/pi/sessions/:sessionId/messages', async (ctx: Context) => {
+  return ctx.json({ success: true });
+});
+
 /**
  * PATCH /api/pi/sessions/:sessionId
  * Update session metadata (e.g., rename)
@@ -162,9 +173,14 @@ piRestRouter.patch('/pi/sessions/:sessionId', async (ctx: Context) => {
       }
     }
 
-    const updatedMeta = await storage.updateSessionMeta(userHome, sessionId, {
-      title: body.title,
-    }, groupSlug);
+    const updatedMeta = await storage.updateSessionMeta(
+      userHome,
+      sessionId,
+      {
+        title: body.title,
+      },
+      groupSlug,
+    );
 
     return ctx.json({
       success: true,
@@ -246,7 +262,9 @@ piRestRouter.delete('/pi/sessions', async (ctx: Context) => {
   }
 
   const body = await ctx.req.json().catch(() => ({}));
-  const contextFilter = body.context ? { context: body.context as string, contextId: body.contextId as string | undefined } : undefined;
+  const contextFilter = body.context
+    ? { context: body.context as string, contextId: body.contextId as string | undefined }
+    : undefined;
   const userHome = getHomeDir(user.email);
 
   try {
@@ -260,7 +278,12 @@ piRestRouter.delete('/pi/sessions', async (ctx: Context) => {
         // Skip sessions that fail to delete
       }
     }
-    logger.info('Bulk deleted sessions', { email: user.email, deleted, total: sessions.length, context: contextFilter?.context });
+    logger.info('Bulk deleted sessions', {
+      email: user.email,
+      deleted,
+      total: sessions.length,
+      context: contextFilter?.context,
+    });
     return ctx.json({ success: true, deleted });
   } catch (err) {
     logger.error('Failed to bulk delete sessions', { email: user.email, error: String(err) });