Description

Render the repo's own backlog/tasks/*.md as a read-only GitHub-issues-style surface. go-git reads the files in-repo at the chosen ref; no separate store. Editing stays in backlog CLI + push.

Acceptance Criteria

• #1 internal/backlog reads backlog/tasks/ via gitread, splits YAML frontmatter from md body (yaml.v3)
• #2 /r//issues: list grouped/filtered by status, label chips mapped to theme colors, sorted by ordinal
• #3 /r//issues/: title, status badge, labels, dates, dependencies, goldmark-rendered body + AC
• #4 Repos with no backlog/tasks/ dir hide the Issues tab
• #5 Read-only: no create/edit in the web UI