Fix session persistence and auto-start container system

- Fix session mount path: ~/.claude/ now mounts to /home/node/.claude/
  (container runs as 'node' user with HOME=/home/node, not root)
- Fix ~/.gmail-mcp/ mount path similarly
- Use absolute paths for GROUPS_DIR and DATA_DIR (required for container mounts)
- Auto-start Apple Container system on NanoClaw startup
- Update debug skill with session troubleshooting guide
- Update spec.md with startup sequence and troubleshooting

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.claude/skills/setup/SKILL.md

@@ -33,10 +33,12 @@ If not installed, tell the user:
 Wait for user confirmation, then verify:
 
 ```bash
-container system start 2>/dev/null || true
+container system start
 container --version
 ```
 
+**Note:** NanoClaw automatically starts the Apple Container system when it launches, so you don't need to start it manually after reboots.
+
 ## 3. Configure API Key
 
 Ask the user:
@@ -268,6 +270,10 @@ The user should receive a response in WhatsApp.
 
 **Service not starting**: Check `logs/nanoclaw.error.log`
 
+**Container agent fails with "Claude Code process exited with code 1"**:
+- Ensure Apple Container is running: `container system start`
+- Check container logs: `cat groups/main/logs/container-*.log | tail -50`
+
 **No response to messages**:
 - Verify the trigger pattern matches (e.g., `@AssistantName` at start of message)
 - Check that the chat JID is in `data/registered_groups.json`