feat(tags): Complete tagged task lists system with enhanced use-tag command

- Multi-context task management with full CLI support
- Enhanced use-tag command shows next available task after switching
- Universal --tag flag support across all commands
- Seamless migration with zero disruption
- Complete tag management suite (add, delete, rename, copy, list)
- Smart confirmation logic and data integrity protection
- State management and configuration integration
- Real-world use cases for teams, features, and releases

.taskmaster/state.json

@@ -1,6 +1,6 @@
 {
-  "currentTag": "test-prd-tag",
-  "lastSwitched": "2025-06-13T06:07:05.204Z",
+  "currentTag": "master",
+  "lastSwitched": "2025-06-13T07:11:05.210Z",
   "branchTagMapping": {},
   "migrationNoticeShown": true
 }