Unify OpenCode and Codex starter kits

- Add .shared/prompts/ with tool-neutral prompts
- Add .opencode/config/project.md, rules/, skills/ from opencode-kit
- Add .codex/config/project.md from codex-kit
- Copy .shared/prompts/ to both .opencode/prompts/ and .codex/prompts/
- Add features/INDEX.md and features/README.md
- Update README with unified structure

The two original starter kits are now redundant.

.opencode/skills/deploy/SKILL.md

@@ -0,0 +1,60 @@
+---
+name: deploy
+description: Deploys to Vercel with production-ready checks
+category: devops
+---
+
+# DevOps
+
+Deploys the project to Vercel with production-ready checks.
+
+## When to Use
+
+```
+/deploy
+```
+
+## Skill Steps
+
+1. **Pre-deployment checks**
+   - Run `npm run build` - must succeed
+   - Run `npm run lint` - no errors
+
+2. **Deploy**
+   - Run `vercel --prod`
+   - Capture deployment URL
+
+3. **Verify deployment**
+   - Test the deployed URL
+   - Run smoke tests on key features
+
+4. **Post-deployment**
+   - Update `features/INDEX.md` with deployment URL
+   - Mark feature as "Deployed"
+
+## Rules
+
+- Build must succeed before deployment
+- Lint must pass before deployment
+- Verify deployment URL is accessible
+
+## If Build Fails
+
+1. Fix compilation errors
+2. Re-run `npm run build`
+3. Re-run `npm run lint`
+4. Then deploy
+
+## If Lint Fails
+
+1. Run `npm run lint:fix`
+2. Commit fixes
+3. Re-run `npm run lint`
+4. Then deploy
+
+## Context Recovery
+
+If context is compacted during deployment:
+1. Check if `vercel` deployment completed
+2. Verify deployment URL
+3. Mark as deployed if successful