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/bootstrap.ts

@@ -1,4 +1,6 @@
 import { mkdirSync } from 'node:fs';
+import { join } from 'node:path';
+import { homedir } from 'node:os';
 import { DATA_PATH } from './data-path';
 import { syncSeedSkills } from './sync-skills';
 import { syncSeedTools } from './sync-tools';
@@ -13,14 +15,29 @@ import { startWhatsAppBotIfConfigured } from './channels/whatsapp/bot';
 
 mkdirSync(DATA_PATH, { recursive: true });
 
-async function ensurePiInstalled(): Promise<boolean> {
-  try {
-    const proc = Bun.spawn(['pi', '--version'], { stdout: 'pipe', stderr: 'pipe' });
-    await proc.exited;
-    return proc.exitCode === 0;
-  } catch {
-    return false;
+/** Check common locations for the Pi package directory. */
+async function findPiPackageDir(): Promise<string | null> {
+  const candidates = [
+    join(homedir(), '.npm-global', 'lib', 'node_modules', '@mariozechner', 'pi-coding-agent'),
+    '/usr/local/lib/node_modules/@mariozechner/pi-coding-agent',
+  ];
+  for (const dir of candidates) {
+    if (await Bun.file(join(dir, 'package.json')).exists()) return dir;
   }
+  return null;
+}
+
+async function ensurePiInstalled(): Promise<boolean> {
+  const dir = await findPiPackageDir();
+  if (!dir) return false;
+  try {
+    const pkg = await Bun.file(join(dir, 'package.json')).json();
+    if (pkg.version) {
+      console.log(`[bootstrap] Pi found: ${pkg.version}`);
+      return true;
+    }
+  } catch {}
+  return false;
 }
 
 async function installPi(): Promise<boolean> {