Reapply "Strengthen search breadth and modal fitting"

This reverts commit 3f824c4bdf.

TODO.md

@@ -33,7 +33,7 @@
 - Result modal sizing is now being constrained to the viewport, and modal-only source-summary translation is now part of the active implementation path.
 - Card summaries now also translate lazily to Korean, and Gemini negative-assessment handling now drives stronger follow-up search behavior than before.
 - Search preview delivery is now moving away from persistent on-disk preview caching toward live proxy / live transcode behavior, with Google Video preview reuse added to result cards and modal playback.
-- The latest search-breadth / modal-fitting experiment from `5ca7aef` has been rolled back after live regression was confirmed.
+- Search breadth and Gemini review budget were widened again because the latest user feedback still reported a thin visible result count even after smarter filtering.
 
 ## Current Architecture
 - `backend/main.go`
@@ -232,7 +232,7 @@
 - Source Summary translation now depends on Google Translate HTTP availability; frontend silently falls back to original summary text if translation fails.
 - The result modal should now stay within viewport height, but this still needs real browser confirmation on multiple short-height displays because CSS-only constraints were the source of the latest user-visible regression.
 - Artgrid preview playback now has a server-side ffmpeg transcode path for `.m3u8` style preview URLs, but this trades storage savings for runtime CPU cost.
-- The reverted `5ca7aef` experiment showed that simply widening collector caps and Gemini candidate count can backfire when the added candidates are weak: final visible count fell sharply even though backend raw candidate count increased.
+- The provided Artgrid HTML sample still does not expose a direct preview `m3u8` or `mp4` URL by itself, and `yt-dlp` probe on the sample clip URL returned `Unsupported URL`, so fully reliable Artgrid playback still depends on live-page/runtime preview discovery succeeding elsewhere in the pipeline.
 - The local self-test script is better than before, but it is still a smoke test, not full integration coverage.
 
 ## Current Risks Around Search Quality
@@ -559,6 +559,7 @@
 - [ ] Browser-verify the new result modal at multiple viewport heights and confirm translated Source Summary readability on real long descriptions
 - [ ] Evaluate whether the new Gemini supplemental-query generation is reducing irrelevant results on a small fixed benchmark query set
 - [ ] Measure runtime cost of live Artgrid preview transcoding and decide whether bounded in-memory throttling or concurrency caps are needed
+- [ ] If Artgrid playback is still required for previewless clips, investigate a browser-rendered fetch path or clip-page asset bundle analysis because static HTML + `yt-dlp` probe were both insufficient on the supplied sample
 - [ ] Revisit Google Video UX:
   - current YouTube embed was abandoned due error `153`
   - current in-app panel is more reliable but less rich than a true embedded watch page
@@ -626,22 +627,22 @@
 ## Recent Change Log
 - Date: `2026-03-17`
 - What changed:
-  - Reverted commit `5ca7aef` (`Strengthen search breadth and modal fitting`) to restore the previous stable search/modal baseline.
-  - Revalidated the rollback state locally.
+  - Raised search breadth again by widening per-source collector caps, increasing the number of base queries considered, increasing per-collector query budgets, and expanding the Gemini candidate review budget.
+  - Added another browser-resolution-aware modal fitting pass: the result popup now recalculates shell width, shell height, media max height, and compact-mode behavior from `window.innerWidth` / `window.innerHeight` when opened or when the viewport changes.
+  - Removed the fixed minimum heights on the lower modal panels so they can shrink with the viewport instead of forcing the popup past the visible browser area.
+  - Checked the supplied Artgrid clip HTML and a direct `yt-dlp` probe against `https://artgrid.io/clip/355470/...`; the HTML still exposes metadata and thumbnail signals only, and the direct probe returned `Unsupported URL`.
 - Why it changed:
-  - The user reported that search results became too sparse again and that `search returned partial results to avoid gateway timeout` reappeared.
-  - The provided log `ai-media-hub-2026-03-17T04-19-08-889Z.log` showed:
-    - backend candidate pool still reaching `30`
-    - Gemini candidate cap widened to `24`
-    - `visualRejectCount: 12`
-    - final visible result count collapsing to `5`
-  - That indicates the widened experiment increased weak/low-visual candidates and pushed the request back toward deadline pressure without improving visible result count.
+  - The user reported that the popup still overflowed the browser viewport and that the visible result set still felt too thin despite the earlier search-expansion work.
+  - The attached Artgrid HTML sample was intended to verify whether a stable preview URL could be extracted directly from static clip HTML.
 - How it was verified:
   - `go test ./...`
   - `bash scripts/selftest.sh`
+  - `python3 -m py_compile worker/downloader.py scripts/mock_searxng.py`
+  - `python3 worker/downloader.py --mode probe --url 'https://artgrid.io/clip/355470/couple-woman-man-holding-hand'`
 - What is still risky or incomplete:
-  - This rollback restores the earlier baseline but does not solve the underlying request to improve visible result count.
-  - The next attempt should start from the reverted baseline and target the actual bottleneck between ranked pool and final merge, instead of only widening raw query breadth.
+  - The new modal layout now adapts to actual browser viewport dimensions in code, but a live browser confirmation on the exact user display is still needed.
+  - Widening search breadth and Gemini review budget should improve visible count, but it can also increase latency and token cost under poor upstream conditions.
+  - The supplied Artgrid HTML sample alone was not enough to derive a directly playable preview URL, so previewless Artgrid clips may still fall back to thumbnail-only behavior.
 
 - Date: `2026-03-17`
 - What changed: