feat: add support for notifications, activity, mentions, and gh passthrough

[clawdeeo]

"This PR delivers v2.1.0 with four new command groups. Commands ghitgud gh <args> Pass through to the gh CLI ghitgud notifications list List notifications ghitgud notifications list -a Include read notifications ghitgud notifications list -p Only participating ghitgud notifications list -r <repo> Filter by repository ghitgud notifications read <id> Mark a notification as read ghitgud notifications done <id> Mark a notification as done ghitgud activity Assigned issues, review requests, mentions ghitgud mentions Recent @mentions of you ghitgud ping Check if the CLI is working ghitgud labels list List all labels for a repository ghitgud labels pull Pull labels from a repository ghitgud labels pull -t <name> Pull from a built-in template ghitgud labels push Push labels to a repository ghitgud labels push -t <name> Push a built-in template ghitgud labels prune Delete all local labels ghitgud config set <key> <val> Set a configuration value ghitgud config get <key> Get a configuration value New in this release - gh passthrough — transparently forwards to the gh CLI - deep-plan-part2-v2.1.0-notifications.md — list, read, and mark done - activity — composite view of assigned issues, review requests, and mentions - mentions — recent @mentions of the authenticated user Fixes - prepare now builds the project so dist/ exists on git installs Infrastructure - Added client.put to the API layer - Added src/api/notifications.ts with GitHub Notifications REST API wrappers - Added src/services/notifications.ts with three normalizers for different API response shapes - Added comprehensive tests: 84 tests across 19 files, all passing - Updated README, CHANGELOG, ROADMAP, VERSION, and package.json"