docs(tracker): add comprehensive production roadmap
Covers 6 phases with full checklists:
- Phase 0: current shipped state (fully documented)
- Phase 1: production hardening (health fixes, rate limiting, tests, security)
- Phase 2: Linear/Jira-parity rich items (markdown, attachments, sub-tasks,
relationships, custom fields, activity log, drag-and-drop Kanban)
- Phase 3: Agent & automation API (claim, PR-link, webhook in/out, SDK, AI triage)
- Phase 4: multi-source intake (public, Slack, email-to-tracker, GitHub/Gitea sync)
- Phase 5: analytics & intelligence (cycle time, SLA alerting, reports)
- Phase 6: mobile & accessibility (PWA, WCAG 2.1 AA, dark mode)
Includes:
- 15 known bugs/gaps table with severity ratings (B-001..B-015)
- Submission guide for public users, internal team, and coding agents
- Full agent API usage examples (claim, PR-link, status update)
- Release schedule through 2026-09-13
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>