Migrate from Claude Code to OpenCode structure

- Move legacy content to legacy/ folder (old, old2, docs, learnings, scripts)
- Create new .opencode/ structure with skills/, tools/, agents/ folders
- Update Makefile to symlink to ~/.config/opencode/ instead of ~/.claude/
- Update Makefile to manage skills, tools, and agents (remove settings.json)
- Simplify install/uninstall (no backup logic)
- Add README.md documenting the new structure
- Keep settings.json as historical reference

legacy/old/skills/roadmap/SKILL.md

@@ -0,0 +1,37 @@
+---
+name: roadmap
+description: >
+  View current issues as a roadmap. Shows open issues organized by status and
+  dependencies. Use when viewing roadmap, checking issue status, or when user
+  says /roadmap.
+model: haiku
+user-invocable: true
+---
+
+# Roadmap View
+
+@~/.claude/skills/gitea/SKILL.md
+
+1. **Fetch all open issues**
+2. **Analyze dependencies** from issue descriptions
+3. **Categorize issues**:
+   - Blocked: Waiting on other issues
+   - Ready: No blockers, can start
+   - In Progress: Has assignee or WIP label
+4. **Present roadmap** as organized list:
+
+```
+## Ready to Start
+- #5: Add user authentication
+- #8: Create dashboard layout
+
+## In Progress
+- #3: Setup database schema
+
+## Blocked
+- #7: User profile page (blocked by #5)
+- #9: Admin dashboard (blocked by #3, #8)
+```
+
+5. **Highlight** any issues that seem stale or unclear
+6. **Suggest** next actions based on the roadmap state