Adds comprehensive test coverage for GitHub tracking across four areas: settings inheritance, issue creation, status sync transitions, and unlink sync regression — spanning 280 lines of new tests across four test files with minimal store.ts adjustment.
Fusion-Task-Id: FN-3876
Implements a tracking auth resolver with forced GitHub client authentication mode, wiring it across the GitHub tracking lifecycle and settings UI. The feature spans six steps: adding the resolver, forced auth mode, routing tracking issue creation through the resolver, and wiring into lifecycle and s
Fusion-Task-Id: FN-3875
Added a GitHub tracking state service (`GitHubTrackingStateService`) and `setIssueState` client method to support closing and reopening tracked issues, with test coverage for both the client and the service, wired into the GitHub routes, and documented in the architecture docs.
Fusion-Task-Id: FN-3873
