[BUG] Cowork VM root disk (9.6GB) too small for real projects — mounted folder competes with OS for space

Description

The Cowork VM root partition is only 9.6GB total (~8.6GB available after OS). The user-mounted folder maps to /sessions/<id>/mnt/ on this same small root disk. For real-world projects with multiple repos, node_modules, and data files, this space fills up instantly — causing ENOSPC errors that break the session.

Environment

• Product: Claude Desktop (Cowork mode)
• OS: macOS (host), Ubuntu 22 (VM)
• VM Disk: 9.6GB root (/dev/sda1), no separate data partition
• Session path: /sessions/<session-id>/ (on root disk)
• Mount path: /sessions/<session-id>/mnt/ (also on root disk)

Steps to Reproduce

1. Open Cowork and select a project folder with moderate size (>2GB)
2. Start working — install npm packages, run builds, create files
3. Run df -h / to see disk usage
4. Within minutes, disk fills to 100% with ENOSPC errors

Observed Behavior

• df -h / shows 9.6GB total, fills to 100% quickly
• npm install fails, file writes fail, even mkdir fails
• Only fix is manually deleting VM caches (/vm_bundles/Cache/Code Cache/)
• Session becomes unusable until cleanup
• Mounted project folder competes with OS/tools for the same 9.6GB

Expected Behavior

• VM should have enough disk for real development work (at least 20-30GB)
• OR mounted folders should be on a separate volume
• OR Cowork should auto-cleanup caches when disk is >90% full

Disk Analysis

Filesystem  Size  Used  Avail  Use%  Mounted on
/dev/sda1   9.6G  8.6G  996M   90%   /

Key space consumers:

• /vm_bundles/ — VS Code server + caches (~3-4GB)
• /sessions/<id>/mnt/ — user mounted project
• No separate /data or /home partition

Suggested Fixes

1. Increase VM disk to 20-30GB
2. Separate partition for user data
3. Auto-cleanup daemon — monitor disk, clear caches at 85%
4. Lazy mount — FUSE/NFS instead of copying project into VM