Add YouTrack pull/push sync with project settings and time tracking.

Wire manual Y menu and CLI sync for issues and work items, persist
per-project credentials, and keep local edits until an explicit push.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/project/store.go

@@ -12,6 +12,8 @@ type Store interface {
 	List() ([]Project, error)
 	Ensure(id string) error
 	Delete(id string) error
+	LoadMeta(id string) (Meta, error)
+	SaveMeta(id string, meta Meta) error
 }
 
 // DirStore discovers projects as subdirectories of dataDir/projects.