improve setup flow: streamline steps, add pre-approval, new manage-mounts skill

- Disable sandbox by default in project settings
- Setup: remove Apple Container option (Docker only), single channel selection
  with plain text list, move fork to end, auto-set empty mounts, add command
  pre-approval step, add UTC timezone confirmation, add wait-on-user guidance,
  add 5m timeouts for long steps
- iMessage: improve Full Disk Access UX with Finder open + drag instructions
- Add /manage-mounts skill for post-setup mount configuration
- Enable iMessage channel import

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.claude/skills/add-imessage-v2/SKILL.md

@@ -31,11 +31,21 @@ npm run build
 
 ### Local Mode (macOS)
 
-Requirements: macOS with Full Disk Access granted to your terminal/Node.js process.
+Requirements: macOS with Full Disk Access granted to the Node.js binary.
 
-1. Go to **System Settings** > **Privacy & Security** > **Full Disk Access**
-2. Add your terminal app (Terminal, iTerm2, etc.) or the Node.js binary
-3. The adapter reads directly from the iMessage database on disk
+The Node binary path is buried deep (e.g. `~/.nvm/versions/node/v22.x.x/bin/node`). To make it easy, open the folder in Finder so the user can drag the file into System Settings:
+
+```bash
+open "$(dirname "$(which node)")"
+```
+
+Then tell the user:
+
+1. Open **System Settings** > **Privacy & Security** > **Full Disk Access**
+2. Click **+**, then drag the `node` file from the Finder window that just opened
+3. Toggle it on
+
+Stop and wait for the user to confirm before continuing.
 
 ### Remote Mode (Photon API)