fix(rust): resolve all clippy warnings treated as errors in CI

Fix 18 clippy errors across 7 files:
- lib.rs: change doc comment to regular comment (empty line after doc)
- arch_audit.rs: replace format!() with string literal, use is_none_or
- code_quality.rs: collapsible if, map_or → is_none_or
- commit.rs: collapsible match guard
- explore.rs: needless_range_loop → iterator enumerate
- skills.rs: map_or(false,...) → is_some_and
- semantic_search.rs: map_or → is_none_or, sort_by → sort_by_key,
  remove explicit type to avoid type_complexity

CI was failing with 'error: could not compile zesdex-infrastructure
due to 18 previous errors' at clippy step.

apps/infrastructure/src/best_practice/commit.rs

@@ -108,13 +108,11 @@ pub fn validate_commit_message(msg: &str) -> Result<(), Vec<String>> {
             // Type-specific rules.
             match type_ {
                 "chore" | "docs" | "refactor" | "test" | "style" | "perf" | "ci" | "build"
-                | "revert" => {
-                    if scope.is_some() {
-                        errors.push(format!(
-                            "'{type_}' commits should not use a scope. \
-                             Only 'feat' and 'fix' require scopes."
-                        ));
-                    }
+                | "revert" if scope.is_some() => {
+                    errors.push(format!(
+                        "'{type_}' commits should not use a scope. \
+                         Only 'feat' and 'fix' require scopes."
+                    ));
                 }
                 _ => {}
             }