Add comprehensive integration test suite using httptest with a mock
Gitea API server. Tests cover GET and POST handlers for dashboard,
issues, pulls, issue/PR detail, create issue, state changes, comments,
labels, assignees, reviews, and settings. Both regular and HTMX
request paths are tested. Includes TestMain to set working directory
to project root for template loading.
Covers issues: #140#139#138#137#136#135#134#133#124#118#113#111#110
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>