[ chebizarro/nostrc ] feat: add GnNostrEventItem model with thread tracking and GListModel implementation

Implement new model layer for event display with GnNostrEventItem wrapper providing thread metadata (root_id, parent_id, reply_depth) and profile association. Add GnNostrEventModel implementing GListModel interface with item caching, profile caching, and thread info tracking via hash tables. Support both timeline and thread view modes with configurable query parameters (kinds, authors, since/until, limit). Include

https://github.com/chebizarro/nostrc/commit/c54507647b670648689ce50ed84d943c43c09a64