fix(p10-1a-1): patch missed SearchHit test-only construction sites

Add repo: None, code_lang: None to the 3 SearchHit struct literals
inside #[cfg(test)] blocks that were missed by the fa4eeb5 sweep.

crates/kebab-rag/tests/common/mod.rs

@@ -171,6 +171,8 @@ pub fn mk_hit_with_indexed_at(
         indexed_at,
         stale: false,
         score_kind: kebab_core::ScoreKind::Rrf,
+        repo: None,
+        code_lang: None,
     }
 }