feat(best_practice): add code quality scanning and commit message validation

- Implemented a code quality scanner that checks for common clean-code violations in Rust source files, including missing documentation, usage of `.unwrap()` in production code, and commented-out code.
- Introduced a commit message validator that follows the Conventional Commits specification, ensuring proper formatting and providing suggestions for invalid messages.
- Created a unified BestPracticeEngine to encapsulate the functionalities of skills, architecture audits, code quality checks, and commit message validation.
- Added tests for both the code quality scanner and commit message validator to ensure reliability and correctness.

apps/infrastructure/skills/commit-convention/SKILL.md

@@ -0,0 +1,87 @@
+---
+name: commit-convention
+description: Enforce commit message convention for features, fixes, chores, and docs
+---
+
+# Commit Message Convention
+
+All commit messages MUST follow one of the four formats below. The type is lowercase. The subject is imperative, lowercase, and has no trailing period.
+
+## Types
+
+### `feat` — New feature or new behaviour
+Scope is required: the name of the affected module.
+
+```
+feat(<module>): <what changed or what feature>
+```
+
+Examples:
+```
+feat(auth): add google oauth sign-in
+feat(billing): support multi-currency invoices
+feat(users): allow avatar upload
+```
+
+### `fix` — Bug fix or issue resolution
+Scope is required: the name of the affected module.
+
+```
+fix(<module>): <what was fixed>
+```
+
+Examples:
+```
+fix(auth): prevent token refresh race condition
+fix(cart): correct total when discount is zero
+fix(api): return 404 instead of 500 on missing user
+```
+
+### `chore` — Housekeeping, dependency bumps, config changes
+No scope.
+
+```
+chore: <what was adjusted>
+```
+
+Examples:
+```
+chore: adjust package.json version (bump)
+chore: update eslint config
+chore: remove unused devDependency
+```
+
+### `docs` — Documentation only
+No scope.
+
+```
+docs: <what changed>
+```
+
+Examples:
+```
+docs: add setup guide to README
+docs: document commit convention
+docs: clarify env variable defaults
+```
+
+## Rules
+
+1. Type is ALWAYS lowercase (`feat`, `fix`, `chore`, `docs`).
+2. `feat` and `fix` REQUIRE a module scope in parentheses.
+3. `chore` and `docs` do NOT use a scope.
+4. Subject line is imperative mood ("add", not "added" or "adds").
+5. Subject line is lowercase, no trailing period.
+6. Keep the subject under ~72 characters.
+7. If a commit needs multiple types, split it into multiple commits.
+
+## Choosing the right type
+
+| Situation | Type |
+|-----------|------|
+| New user-facing capability | `feat` |
+| New internal behaviour | `feat` |
+| Something was broken, now works | `fix` |
+| Version bump in package.json | `chore` |
+| Lockfile regeneration, config tweak | `chore` |
+| README, guide, or comment-only change | `docs` |