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/src/tools/registry.rs

@@ -45,6 +45,9 @@ pub fn all_tools() -> Vec<Box<dyn super::Tool>> {
         Box::new(super::semantic_search::SemanticSearch),
         Box::new(super::semantic_search::RebuildIndex),
         Box::new(super::parallel_delegate::ParallelDelegate),
+        // ── Best-practice tools (built-in) ─────────────────────────
+        Box::new(super::best_practice::BestPractice),
+        Box::new(super::best_practice::CommitConvention),
     ]
 }