Import History & Undo Capability

[krisrowe]

Problem\nUsers need a way to easily audit or rollback import operations (including syncs). Currently, once events are imported, there is no easy record of what was created.\n\n### Proposed Solution\nAutomatically store a record of every import operation in the XDG cache directory (e.g., ~/.cache/gworkspace-access/history/).\n\n#### Features\n- Automatic Logging: Every import_events call should append to a daily or operation-based log.\n- Metadata: Store source profile, timestamp, and list of created event IDs.\n- Undo Command: Implement gwsa calendar undo <OPERATION_ID> (or --last) to delete all events associated with a specific import.\n\n### Implementation Details\n- extend import_events in calendar/sync.py to write to the cache.\n- Create a new CLI command gwsa calendar history and gwsa calendar undo.