- Add projectContext store with load/save via existing Tauri file commands
- Add ProjectContextPanel modal with tabbed editor, file-exists badges, and templates
- Add injectTextStore signal so StatusBar can inject content directly into InputBar
- Add PROJECT_CONTEXT_SYSTEM_ADDENDUM auto-appended to custom_instructions on connect
- Add open-book button to StatusBar to open the panel
- Add PROJECT.md example file for the hikari-desktop project itself
- 34 tests covering all store methods, exports, and signal behaviour
