928e2fa182
Implements the Gitea adapter (gitea.Adapter) that satisfies vcs.Client. Key components: - gitea/adapter.go: Adapter struct wrapping *Client with all vcs.Client methods - gitea/position.go: BuildPositionToLineMap for diff-position → line translation - gitea/adapter_test.go: Tests for all mapping methods and event translation - gitea/position_test.go: Tests for position translation edge cases Translation details: - ReviewEvent: APPROVE → APPROVED (Gitea-native) - PostReview: fetches diff, builds position map, translates each comment - Deletion-targeted positions map to nearest non-deletion line below - All field-mapping methods tested (GetPullRequest, GetPullRequestFiles, ListReviews, GetCommitStatuses, ListContents) Also: - Added Base field to gitea.PullRequest struct - Updated conformance tests to assert Adapter (not raw Client) satisfies vcs.Client - Removed phase2 build tag from conformance tests Closes #79