chore: restore product scaffold to rollback baseline

docs/governance/git-commit-message-convention.md

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+# Chanora Git Commit Message Convention
+
+**Document status:** DV meeting baseline candidate  
+**Date:** 2026-05-29
+
+Chanora uses Conventional Commits style:
+
+```text
+<type>(<scope>): <summary>
+```
+
+Examples:
+
+```text
+feat(voice): add push-to-talk state handling
+fix(protocol): recover channel tree after reconnect snapshot
+sec(diagnostics): redact server password from export bundle
+release(android): prepare internal alpha build metadata
+```
+
+Commits that affect requirements, design, verification, release, security, privacy, or legal gates should update the relevant document in the same change set.