Fix/WA reconnect, container perms, assist name in env (#297)

* fix: WA 515 stream error reconnect exiting early before key sync

Pass isReconnect flag on 515 reconnect so the registered-creds check
doesn't bail out before the handshake completes (caused "logging in..."
hang after successful pairing).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: container permission errors on Docker with non-default uid

Make /home/node world-writable in the Dockerfile so the SDK can write
.claude.json. Add --user flag matching host uid/gid in container-runner
so bind-mounted files are accessible. Skip when running as root (uid 0),
as the container's node user (uid 1000), or on native Windows.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: write ASSISTANT_NAME to .env during setup

When a custom assistant name is chosen, persist it to .env so config.ts
picks it up at runtime. Uses temp file for cross-platform sed
compatibility (macOS/Linux/WSL).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/whatsapp-auth.ts

@@ -41,10 +41,10 @@ function askQuestion(prompt: string): Promise<string> {
   });
 }
 
-async function connectSocket(phoneNumber?: string): Promise<void> {
+async function connectSocket(phoneNumber?: string, isReconnect = false): Promise<void> {
   const { state, saveCreds } = await useMultiFileAuthState(AUTH_DIR);
 
-  if (state.creds.registered) {
+  if (state.creds.registered && !isReconnect) {
     fs.writeFileSync(STATUS_FILE, 'already_authenticated');
     console.log('✓ Already authenticated with WhatsApp');
     console.log(
@@ -110,7 +110,7 @@ async function connectSocket(phoneNumber?: string): Promise<void> {
         // 515 = stream error, often happens after pairing succeeds but before
         // registration completes. Reconnect to finish the handshake.
         console.log('\n⟳ Stream error (515) after pairing — reconnecting...');
-        connectSocket(phoneNumber);
+        connectSocket(phoneNumber, true);
       } else {
         fs.writeFileSync(STATUS_FILE, `failed:${reason || 'unknown'}`);
         console.log('\n✗ Connection failed. Please try again.');