feat(model-capabilities): drive model capabilities and labels from one manifest

[wpfleger96]

Summary

Centralizes model capability knowledge — thinking mode, supported effort levels, wire routes, and human-readable labels — into a single manifest, scripts/model-capabilities.json. Rust and TypeScript each get a small interpreter that reads the same manifest, replacing hand-maintained tables scattered across both languages that had already drifted apart. A capability change is now a data edit, not parallel edits to two code paths. Supersedes the codegen approach explored in #3603.

A cross-language contract keeps the two interpreters honest: scripts/normative-corpus.json is a golden snapshot generated from the Rust resolver (103 vectors covering all six capability axes) and replayed natively in TS. CI fails if either language disagrees with the corpus or the corpus drifts from the resolver. Regenerate with just regen-model-corpus.

Behavior changes

• Effort dropdown for openai-compat providers no longer offers max. The request path always clamped max to xhigh on the wire, so the UI stops offering a value that was silently rewritten. UI-only, wire-identical.
• Databricks v2 routing (wire-visible): uncurated endpoint names carrying a bare Claude code-name segment (e.g. goose-opus-5) now route to the MLflow chat wire instead of Anthropic Messages — they lose Anthropic prompt caching but still succeed on a valid OpenAI-compatible wire. Curated databricks-claude-* records and any name starting with claude are unchanged. A handful of other uncurated/adversarial name shapes similarly fall back to MLflow chat instead of pattern-matched routes; every curated model resolves identically to before, all axes.
• Curated model labels on the real discovery path. The Databricks API returns no display name, so discovery emits the raw endpoint id as the model name ({id, name: id}) on every path. ModelEntry.name is now curated at all four construction seams in buzz-agent — v2 discovery, v1 parse, the auth-empty default catalog, and the configured-model fallback — via a read-only databricks_registry_label lookup over the manifest's databricks_v2 exact records; id stays the raw wire/config value. A known id renders its curated label (databricks-gpt-5-5 → GPT-5.5), an unknown id passes through unchanged, and the default-catalog row reads GPT-5.5 (default catalog). As a defense against older buzz-agent binaries and any harness that echoes ids, resolveModelLabel treats a discovered name equal to the trimmed id as absent and falls through to the registry tier; a genuinely distinct name (including the suffixed default-catalog label) still wins.

Cleanup

Deletes the duplicated capability tables and their tests: the config.rs gpt5 matchers, effort tables, and clamp logic; the legacy segment-based Databricks v2 route classifier in llm.rs; and the TS hand tables plus effortTable.fixture.json. All are replaced by manifest lookups through the shared resolver — no line of capability data exists in two places.