Data-only contributions: per-model JSON registry, validation, PR CI

Contributors no longer touch site code. Model registration moves from
cases.ts literals to repo-root models/<model-id>.json files (filename =
model id = outputs/ folder); cases move to cases.json; cases.ts now just
derives MODELS/RUNS via import.meta.glob. Parallel PRs stop conflicting
because each model owns its own file.

scripts/validate-data.ts runs inside `bun run build` and a new PR CI
workflow: dash-only ids, required bilingual provenance note per run,
declared artifacts must exist, no orphan outputs/ dirs.

Also: run notes render whitespace-pre-wrap (multi-line notes, idea from
PR #2), README contribution guide rewritten around the JSON template,
CLAUDE.md updated, OG card refreshed for the DeepSeek merge.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

models/glm-5-1.json

@@ -0,0 +1,5 @@
+{
+  "label": "GLM-5.1",
+  "vendor": "Zhipu AI",
+  "order": 120
+}