Refine result modal and Gemini recovery

TODO.md

@@ -255,6 +255,22 @@
   - backend debug broadcasts
 
 ## Recent Change Log
+- Date: `2026-03-16`
+- What changed:
+  - Result modal layout was rebuilt to match a top `16:9` embedded viewer with bottom-left full AI note and bottom-right action panel.
+  - Google Video results now load YouTube embed URLs in the modal viewer and keep the white `Direct Download` action in the lower-right panel.
+  - When Gemini evaluation comes back mostly negative or too weak, the backend now runs one supplemental search pass with broader intent variants and reevaluates the merged pool.
+  - Failed Gemini batch evaluations now retry sequentially candidate-by-candidate with a short delay so more candidates can still be processed when batch/token evaluation is unstable.
+- Why it changed:
+  - The requested modal information hierarchy was different from the previous implementation.
+  - The user wanted negative Gemini feedback to trigger more exploration instead of stopping at the first pool.
+  - Batch-level Gemini failures were causing too many results to skip evaluation entirely.
+- How it was verified:
+  - code-path inspection against the updated modal wiring and search flow
+- What is still risky or incomplete:
+  - Non-YouTube third-party pages can still refuse iframe embedding via CSP or `X-Frame-Options`.
+  - Sequential Gemini retries improve coverage but also increase latency when the model is degraded.
+
 - Date: `2026-03-16`
 - What changed:
   - Bumped frontend asset version and added result-modal initialization guards to avoid click failures when browser cache serves mismatched HTML/JS.