fix(fb-38): add score_kind to remaining SearchHit literals

Add missing score_kind field to SearchHit constructors in:
- kebab-tui/tests/search.rs::make_hit()
- kebab-eval/tests/metrics_and_compare.rs::hit()
- kebab-eval/src/metrics.rs::hit()

All test fixtures default to Rrf (hybrid mode), matching the field's
Default impl and the test semantics.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-tui/tests/search.rs

@@ -55,6 +55,7 @@ fn make_hit(rank: u32, path: &str, snippet: &str, citation: Citation) -> SearchH
         // staleness rendering covered in dedicated tests (Task 11).
         indexed_at: time::OffsetDateTime::UNIX_EPOCH,
         stale: false,
+        score_kind: kebab_core::ScoreKind::Rrf,
     }
 }