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/arch_audit.rs

@@ -181,7 +181,7 @@ fn scan_file(
         if trimmed.starts_with("use ") {
             for &forbidden in forbidden {
                 let pattern = format!("use {forbidden}");
-                if trimmed.starts_with(&pattern) || trimmed.starts_with(&format!("use crate::")) {
+                if trimmed.starts_with(&pattern) || trimmed.starts_with("use crate::") {
                     // `use crate::` in domain could reference domain-only items — skip.
                     continue;
                 }
@@ -234,11 +234,11 @@ pub fn audit_layering(root: &Path) -> Result<AuditReport> {
     let mut files_scanned = 0;
 
     for entry in Walk::new(&apps_dir).flatten() {
-        if entry.file_type().map_or(true, |ft| !ft.is_file()) {
+        if entry.file_type().is_none_or(|ft| !ft.is_file()) {
             continue;
         }
         let path = entry.path();
-        if path.extension().map_or(true, |e| e != "rs") {
+        if path.extension().is_none_or(|e| e != "rs") {
             continue;
         }