- Add GET /api/model/info endpoint that resolves model metadata using the
same 10-step context-length detection chain the agent uses. Returns
auto-detected context length, config override, effective value, and
model capabilities (tools, vision, reasoning, max output, model family).
- Surface model.context_length as model_context_length virtual field in
the config normalize/denormalize cycle. 0 = auto-detect (default),
positive value overrides. Writing 0 removes context_length from the
model dict on disk.
- Add ModelInfoCard component showing resolved context window (e.g. '1M
auto-detected' or '500K override — auto: 1M'), max output tokens, and
colored capability badges (Tools, Vision, Reasoning, model family).
- Inject ModelInfoCard between model field and context_length override in
ConfigPage General tab. Card re-fetches on model change and after save.
- Insert model_context_length right after model in CONFIG_SCHEMA ordering
so the three elements (model input → info card → override) are adjacent.
