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/verify.md

@@ -0,0 +1,67 @@
+---
+description: Run verification loop to validate implementation
+agent: build
+---
+
+# Verify Command
+
+Run verification loop to validate the implementation: $ARGUMENTS
+
+## Your Task
+
+Execute comprehensive verification:
+
+1. **Type Check**: `npx tsc --noEmit`
+2. **Lint**: `npm run lint`
+3. **Unit Tests**: `npm test`
+4. **Integration Tests**: `npm run test:integration` (if available)
+5. **Build**: `npm run build`
+6. **Coverage Check**: Verify 80%+ coverage
+
+## Verification Checklist
+
+### Code Quality
+- [ ] No TypeScript errors
+- [ ] No lint warnings
+- [ ] No console.log statements
+- [ ] Functions < 50 lines
+- [ ] Files < 800 lines
+
+### Tests
+- [ ] All tests passing
+- [ ] Coverage >= 80%
+- [ ] Edge cases covered
+- [ ] Error conditions tested
+
+### Security
+- [ ] No hardcoded secrets
+- [ ] Input validation present
+- [ ] No SQL injection risks
+- [ ] No XSS vulnerabilities
+
+### Build
+- [ ] Build succeeds
+- [ ] No warnings
+- [ ] Bundle size acceptable
+
+## Verification Report
+
+### Summary
+- Status: ✅ PASS / ❌ FAIL
+- Score: X/Y checks passed
+
+### Details
+| Check | Status | Notes |
+|-------|--------|-------|
+| TypeScript | ✅/❌ | [details] |
+| Lint | ✅/❌ | [details] |
+| Tests | ✅/❌ | [details] |
+| Coverage | ✅/❌ | XX% (target: 80%) |
+| Build | ✅/❌ | [details] |
+
+### Action Items
+[If FAIL, list what needs to be fixed]
+
+---
+
+**NOTE**: Verification loop should be run before every commit and PR.