FUSE: Implement archive mounting operations

[efimsky]

Parent Issue

Part of #118 (FUSE-based Archive & Remote Browsing Feature)

Summary

Implement archive mounting, unmounting, and cleanup operations in MountManager.

Dependencies

Requires #119 (MountManager core infrastructure)

Tasks

Mount Operations

• Implement mount_archive(archive_path) - Mount archive using archivemount or fuse-archive
  • Check if already mounted (reuse existing mount)
  • Generate mount point path using hash
  • Create mount point directory
  • Execute archivemount or fuse-archive via subprocess
  • Track mount in active_mounts
  • Return mount point Path or None on failure

Unmount Operations

• Implement unmount(mount_point) - Unmount a single mount

  • Call fusermount -u on Linux or umount on macOS
  • Remove from active_mounts
  • Clean up mount point directory
  • Return success boolean

• Implement unmount_all() - Unmount all active mounts

  • Iterate over copy of active_mounts keys
  • Call unmount() for each

Cleanup Operations

• Implement _cleanup_stale_mounts() - Clean crashed session leftovers

  • Check if MOUNT_BASE exists
  • Iterate over subdirectories
  • Try to unmount each (may not be mounted)
  • Remove directories

• Implement _try_unmount(mount_point) - Best-effort unmount without tracking

Utility Methods

• Implement is_in_mount(path) - Check if path is inside any active mount
• Implement get_mount_for_path(path) - Get MountInfo for path if in mount

Testing

• Test mount_archive() creates mount point directory
• Test mount_archive() calls archivemount with correct args
• Test mount_archive() tracks mount in active_mounts
• Test mount_archive() returns None on subprocess failure
• Test mount_archive() reuses existing mount for same archive
• Test mount_archive() uses fuse-archive as fallback
• Test unmount() calls fusermount/umount
• Test unmount() removes from active_mounts
• Test unmount() removes mount point directory
• Test unmount() returns False for unknown mount
• Test unmount_all() unmounts all active mounts
• Test is_in_mount() for paths inside/outside mounts
• Test get_mount_for_path() returns correct MountInfo

Files

• Modify: tnc/mount.py
• Modify: tests/test_mount.py