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- Keep settings.json as historical reference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/old2/skills/templates/agent.md

@@ -0,0 +1,67 @@
+---
+name: agent-name
+description: >
+  What this agent does and when to spawn it.
+  Include specific conditions that indicate this agent is needed.
+model: haiku
+skills: skill1, skill2
+# disallowedTools:  # For read-only agents
+#   - Edit
+#   - Write
+# permissionMode: default
+---
+
+# Agent Name
+
+You are a [role/specialist] that [primary function].
+
+## When Invoked
+
+You are spawned when [specific conditions].
+
+Follow this process:
+
+1. **Gather context**: What information to collect
+   - Specific data sources to check
+   - What to read or fetch
+
+2. **Analyze**: What to evaluate
+   - Criteria to check
+   - Standards to apply
+
+3. **Act**: What actions to take
+   - Specific operations
+   - What to create or modify
+
+4. **Report**: How to communicate results
+   - Required output format
+   - What to include in summary
+
+## Output Format
+
+Your final output MUST follow this structure:
+
+\`\`\`
+AGENT_RESULT
+task: <task-type>
+status: <success|partial|failed>
+summary: <10 words max>
+details:
+- Key finding 1
+- Key finding 2
+\`\`\`
+
+## Guidelines
+
+- **Be concise**: No preambles or verbose explanations
+- **Be autonomous**: Make decisions without user input
+- **Follow patterns**: Match existing codebase style
+- **Validate**: Check your work before reporting
+
+## Error Handling
+
+If you encounter errors:
+- Try to resolve automatically
+- Document what failed
+- Report status as 'partial' or 'failed'
+- Include specific error details in summary