Make the vision judge discover cost-effective OpenRouter models

Add openrouter_judge.py to rank live image+JSON models by advertised price,
with ordered fallbacks, auth-error handling and auto selection. Wire both judges
to --model auto, record the model used, and add fake-catalogue/mocked-call
tests. Re-run the judges with the valid key: 13/13 screen designs match, 0 diff;
the Forward+ A/B report records the selected model and ~$0.006 spend. Headless
231/231, Python 94/94.

CHANGELOG.md

@@ -4,6 +4,25 @@ All notable user-facing changes to Gig Line. The format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and versions use
 Semantic Versioning.
 
+## [0.7.2] — 2026-11-01
+
+### Added
+
+- Automatic OpenRouter model selection for the screenshot judges: the cheapest
+  currently available image+JSON-capable model is used, with ordered fallbacks
+  and a pinned `GIG_LINE_JUDGE_MODEL`/`--model` override.
+
+### Changed
+
+- The judge reports the model that produced each verdict and fails clearly on an
+  invalid API key instead of retrying other models.
+- The screen-design and realism reports now include the fresh judge results.
+
+### Fixed
+
+- The blocked screenshot judge now runs with the valid `OPENROUTER_API_KEY`
+  (`13/13` screen designs match, `0` diff).
+
 ## [0.7.1] — 2026-11-01
 
 ### Added