feat: complete OpenCode plugin support with hooks, tools, and commands

Major OpenCode integration overhaul:

- llms.txt: Comprehensive OpenCode documentation for LLMs (642 lines)
- .opencode/plugins/ecc-hooks.ts: All Claude Code hooks translated to OpenCode's plugin system
- .opencode/tools/*.ts: 3 custom tools (run-tests, check-coverage, security-audit)
- .opencode/commands/*.md: All 24 commands in OpenCode format
- .opencode/package.json: npm package structure for opencode-ecc
- .opencode/index.ts: Main plugin entry point

- Delete incorrect LIMITATIONS.md (hooks ARE supported via plugins)
- Rewrite MIGRATION.md with correct hook event mapping
- Update README.md OpenCode section to show full feature parity

OpenCode has 20+ events vs Claude Code's 3 phases:
- PreToolUse → tool.execute.before
- PostToolUse → tool.execute.after
- Stop → session.idle
- SessionStart → session.created
- SessionEnd → session.deleted
- Plus: file.edited, file.watcher.updated, permission.asked, todo.updated

- 12 agents: Full parity
- 24 commands: Full parity (+1 from original 23)
- 16 skills: Full parity
- Hooks: OpenCode has MORE (20+ events vs 3 phases)
- Custom Tools: 3 native OpenCode tools

The OpenCode configuration can now be:
1. Used directly: cd everything-claude-code && opencode
2. Installed via npm: npm install opencode-ecc

.opencode/commands/refactor-clean.md

@@ -0,0 +1,102 @@
+---
+description: Remove dead code and consolidate duplicates
+agent: refactor-cleaner
+subtask: true
+---
+
+# Refactor Clean Command
+
+Analyze and clean up the codebase: $ARGUMENTS
+
+## Your Task
+
+1. **Detect dead code** using analysis tools
+2. **Identify duplicates** and consolidation opportunities
+3. **Safely remove** unused code with documentation
+4. **Verify** no functionality broken
+
+## Detection Phase
+
+### Run Analysis Tools
+
+```bash
+# Find unused exports
+npx knip
+
+# Find unused dependencies
+npx depcheck
+
+# Find unused TypeScript exports
+npx ts-prune
+```
+
+### Manual Checks
+
+- Unused functions (no callers)
+- Unused variables
+- Unused imports
+- Commented-out code
+- Unreachable code
+- Unused CSS classes
+
+## Removal Phase
+
+### Before Removing
+
+1. **Search for usage** - grep, find references
+2. **Check exports** - might be used externally
+3. **Verify tests** - no test depends on it
+4. **Document removal** - git commit message
+
+### Safe Removal Order
+
+1. Remove unused imports first
+2. Remove unused private functions
+3. Remove unused exported functions
+4. Remove unused types/interfaces
+5. Remove unused files
+
+## Consolidation Phase
+
+### Identify Duplicates
+
+- Similar functions with minor differences
+- Copy-pasted code blocks
+- Repeated patterns
+
+### Consolidation Strategies
+
+1. **Extract utility function** - for repeated logic
+2. **Create base class** - for similar classes
+3. **Use higher-order functions** - for repeated patterns
+4. **Create shared constants** - for magic values
+
+## Verification
+
+After cleanup:
+
+1. `npm run build` - builds successfully
+2. `npm test` - all tests pass
+3. `npm run lint` - no new lint errors
+4. Manual smoke test - features work
+
+## Report Format
+
+```
+Dead Code Analysis
+==================
+
+Removed:
+- file.ts: functionName (unused export)
+- utils.ts: helperFunction (no callers)
+
+Consolidated:
+- formatDate() and formatDateTime() → dateUtils.format()
+
+Remaining (manual review needed):
+- oldComponent.tsx: potentially unused, verify with team
+```
+
+---
+
+**CAUTION**: Always verify before removing. When in doubt, ask or add `// TODO: verify usage` comment.