feat: Add SOLID principles and TDD reference documentation

- Created solid.md to document the SOLID principles for clean code practices.
- Created tdd.md to outline Test Driven Development principles and practices.
- Added kana-rust-backend-best-practice.md as a reference guide for building a Rust backend using Axum and SeaORM.
- Established push-flow-convention.md to enforce pre-commit and pre-push hooks with versioning rules.
- Introduced AGENTS.md to provide guidance on best practices and available commands for Kilo.
- Configured kilo.json to include new skills and agents for enhanced functionality.
- Added lefthook.yml for managing git hooks to ensure code quality and adherence to conventions.

lefthook.yml

@@ -0,0 +1,37 @@
+# Lefthook hooks for zesdex — Rust workspace
+# Install: lefthook install
+# https://lefthook.dev/
+
+pre-commit:
+  commands:
+    cargo-fmt:
+      glob: "*.rs"
+      run: cargo fmt --check -- {staged_files}
+      stage_fixed: true
+    cargo-clippy:
+      glob: "*.rs"
+      run: cargo clippy --workspace -- -D warnings
+
+pre-push:
+  commands:
+    cargo-check:
+      run: cargo check --workspace
+    cargo-clippy:
+      run: cargo clippy --workspace -- -D warnings
+    cargo-test:
+      run: cargo test --workspace
+    cargo-doc:
+      run: cargo doc --workspace --no-deps 2>&1 | head -20
+
+commit-msg:
+  commands:
+    commitlint:
+      run: |
+        echo "{1}" | grep -qE '^(feat\([a-z]+\)|fix\([a-z]+\)|chore:|docs:|refactor:|test:|perf:|build:|ci:|style:|revert): .+$' || {
+          echo "ERROR: Commit message does not follow Conventional Commits format."
+          echo "  feat(scope): description"
+          echo "  fix(scope): description"
+          echo "  chore: description"
+          echo "  docs: description"
+          exit 1
+        }