feat: [QA][POLICY] Branch Protection + Mandatory Review Policy for All Repos (#918)

Refs #918
Agent: groq

CONTRIBUTING.md

@@ -299,3 +299,47 @@ All repositories enforce:
 CODEOWNERS
 ```text
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+# Contribution & Code Review Policy
+
+## Branch Protection Rules
+All repositories must:
+- ✅ Require PR for merge
+- ✅ Require 1 approval
+- ✅ Dismiss stale approvals
+- ⚠️ Require CI to pass (where exists)
+- ✅ Block force push
+- ✅ block branch deletion
+
+## Review Requirements
+- 🧑 Default reviewer: `@perplexity` for all repos
+- 🧑 Required reviewer: `@Timmy` for `hermes-agent/`
+
+## Workflow
+1. Create feature branch from `main`
+2. Submit PR with clear description
+3. Wait for @perplexity review
+4. Address feedback if any
+5. Merge after approval and passing CI
+
+## CI/CD Requirements
+- All main branch merges require:
+  - ✅ Linting
+  - ✅ Unit tests
+  - ⚠️ Integration tests (pending for the-nexus)
+  - ✅ Security scans
+
+## Exceptions
+- Emergency hotfixes require:
+  - ✅ @Timmy approval
+  - ✅ Post-merge documentation
+  - ✅ Follow-up PR for full review
+
+## Abandoned PRs
+- PRs inactive >7 days: 🧹 archived
+- Unreviewed PRs >14 days: ❌ closed
+
+## CI Status
+- ✅ hermes-agent: ci active
+- ⚠️ the-nexus: ci runner dead (see #915)
+- ✅ timmy-home: No ci
+- ⚠️ timmy-config: Limited ci