Revert "Reduce noisy Gemini batch failure warnings"

This reverts commit 6faff4d269.

TODO.md

@@ -233,7 +233,6 @@
 - 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.
-- Gemini Vision batch execution can still see mixed failure modes: true model/output-format failures and ignorable low-value/no-visual candidate skips. These should not be conflated in user-facing warnings.
 - 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
@@ -555,7 +554,6 @@
 ## Highest-Value Next Steps
 - [ ] Reduce `/api/search` latency further without collapsing result count
 - [ ] Rebuild the reverted search-expansion work from the previous stable baseline, but only after measuring where candidate quality collapses between ranked pool and final merge
-- [ ] Continue hardening Gemini response parsing so truncated JSON or mixed-quality candidate batches degrade more gracefully without surfacing alarming warnings
 - [ ] Build a repeatable repo-local bootstrap script or documented setup command set for non-root machines so fresh PC setup does not depend on shell history
 - [ ] Improve Envato / Artgrid preview acquisition reliability so Gemini Vision sees real frames more often
 - [ ] Browser-verify the new result modal at multiple viewport heights and confirm translated Source Summary readability on real long descriptions
@@ -626,25 +624,6 @@
 - If behavior in the browser does not match the latest backend/frontend code, the first assumption should be stale frontend assets until proven otherwise
 
 ## Recent Change Log
-- Date: `2026-03-17`
-- What changed:
-  - Reduced Gemini Vision batch size from `8` to `6` candidates to lower the chance of oversized/truncated JSON responses.
-  - Added an explicit Gemini output token cap for the vision JSON response path.
-  - Changed Gemini batch failure accounting so ignorable per-candidate skips such as low-value thumbnails or missing visuals no longer count as a user-facing partial batch failure when useful recommendations were still recovered.
-  - Added unit coverage for the hard-error filtering behavior.
-- Why it changed:
-  - The user reported the warning `gemini vision partially failed on 2 of 2 batches`.
-  - The provided log `ai-media-hub-2026-03-17T04-35-33-028Z.log` showed two distinct failure classes during the second repeated search:
-    - a real batch-level JSON extraction failure caused by truncated Gemini output
-    - multiple ignorable sequential-retry skips caused by low-value thumbnails or missing visuals
-  - Those were being combined into an alarming partial-failure warning even though useful recommendations were still recovered.
-- How it was verified:
-  - `go test ./...`
-  - `bash scripts/selftest.sh`
-- What is still risky or incomplete:
-  - This reduces false-positive partial-failure warnings, but true Gemini output truncation can still happen occasionally if model behavior changes again.
-  - Further hardening may still be needed if Gemini starts returning different malformed JSON shapes.
-
 - Date: `2026-03-17`
 - What changed:
   - Reverted commit `5ca7aef` (`Strengthen search breadth and modal fitting`) to restore the previous stable search/modal baseline.