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/skills.rs

@@ -35,7 +35,7 @@ impl EmbeddedSkills {
                 match entry {
                     DirEntry::Dir(sub) => walk(sub, skills),
                     DirEntry::File(file) => {
-                        if file.path().file_name().map_or(false, |n| n == "SKILL.md") {
+                        if file.path().file_name().is_some_and(|n| n == "SKILL.md") {
                             if let Some(parent) = file
                                 .path()
                                 .parent()