* Fix paths in permission window to show relative paths

* Fix paths in permission window to show actual file paths

…ns (#26)

BREAKING CHANGE: Replaces dual-container setup with unified container

Merges opencode_sandbox and opencode_with_ssh into single unified 
container accessible via both docker exec (Mac) and SSH (iPhone).

Major improvements:
- Single container with dual access (docker exec + SSH)
- Persistent screen sessions shared between devices
- Smart helper script (scripts/opencode) auto-attaches or creates
- GitHub CLI available from all access methods
- Docker socket access for MCP servers
- Dynamic Docker GID detection (cross-platform compatible)
- Robust screen session initialization (no race conditions)

Components added:
- Dockerfile.opencode-unified (merged features from both old Dockerfiles)
- docker-compose.yml (unified compose with Tailscale sidecar)
- entrypoint-unified.sh (SSH daemon + gh auth + screen session)
- scripts/opencode (smart launcher with attach logic)
- .screenrc (persistent session config)
- docs/session-management.md (usage guide)
- MIGRATION.md (upgrade guide)
- tests/test_unified_container.bats (test suite)

Review process:
- Initial review: 7 issues found (3 critical, 4 major)
- Fixes applied in f1a7b7d
- Re-review: All issues verified fixed, APPROVED

Closes #25