Sub-Issue 3: Implement Auto-Migration Logic

[leppikallio]

Parent Issue: #84
Estimated Time: ~25 minutes
Phase: 3 (Parallel with Sub-Issue 4)

Goal

Auto-migrate config on first run - create user config with vault_location and migrate oauth.client_id from repo config.

Files

• Modify: .workspace/scripts/config.py (add migration function)
• Modify: .workspace/config.yaml (remove oauth.client_id during migration)
• Test: .workspace/tests/test_config_migration.py (new file)

Dependencies

Requires: Sub-Issues 1 & 2 completed
Phase: Phase 3 (parallel with Sub-Issue 4)

Implementation Steps

See full implementation steps in issue #84 under "Sub-Issue 3: Implement Auto-Migration Logic"

Summary

1. Write failing tests for migration (4 tests)
2. Implement _migrate_config() function
3. Add migration call to load_config()
4. Run tests to verify they pass
5. Test migration with real config
6. Run type checker
7. Commit changes
8. Close this sub-issue

Key Requirements

• CRITICAL: Use atomic writes (temp file → chmod 0o600 → os.replace)
• Never delete or corrupt existing files
• Follow OAuth storage pattern (.workspace/scripts/oauth/storage.py:136-175)
• Set 0o600 permissions on user config
• Preserve user config if it already exists

Acceptance Criteria

• Creates ~/.config/vipunen/config.yaml on first run
• Sets vault_location from cwd
• Moves oauth.client_id from repo to user config
• Removes oauth section from repo config
• Sets 0o600 permissions on user config
• Preserves existing user config (no overwrite)
• All tests pass
• Type checking passes

Testing Commands

uv run pytest .workspace/tests/test_config_migration.py -v
uv run pyright .workspace/scripts/config.py