v0.26.0:0 - disk-driven model menu (scan sparks; recipes; needs-setup)

The dashboard menu is now the set of models actually downloaded on the
Sparks, not a hard-coded catalog. models.yaml + overrides are reframed as
launch recipes matched to an on-disk model by repo; an on-disk model with
no recipe is flagged needs_setup and its launch settings are inferred from
its config.json for a one-time operator confirmation (discovery.py).

- delete now removes weights AND the menu card (delete_from_disk sweeps all
  hosts; the delete endpoint resolves keys via the live menu)
- new GET /api/models/suggest; /api/models returns the menu + a recipes list
  (download autocomplete); GET /api/models/disk-status removed
- dropped the two legacy Qwen recipes (235B FP8, 2.5 72B)
- tests: +test_discovery.py (cache parsing, infer_recipe, build_menu merge)

docs/guides/fastapi-image.md

@@ -39,6 +39,7 @@ Two kinds, both run with the `image/.venv` interpreter (system python3 has no de
 ## Layout
 
 - `image/app/server.py` — FastAPI entry; routers live in sibling modules (`audio_proxy.py`, `llm_proxy.py`, `embeddings_proxy.py`, `redaction_gateway.py`, `swap.py`, `health.py`, `deep_health.py`, `connectivity.py`, …).
+- `image/app/discovery.py` — the disk-driven model menu. `/api/models` lists what's actually downloaded on the Sparks (via `disk.list_cached_models`); `models.yaml`/overrides are *launch recipes* matched by repo, not the menu. An on-disk model with no recipe is `needs_setup` → `infer_recipe` reads its `config.json` to prefill a setup form the operator confirms once.
 - `image/app/static/` — the dashboard UI.
-- `image/models.yaml` — vLLM model catalog bundled into the image.
+- `image/models.yaml` — bundled vLLM **launch recipes** (how to launch a known model), NOT the dashboard menu — the menu is the on-disk scan.
 - `image/spark_embed/` — Dockerfile + app for the embeddings container; built ON a Spark (ARM64, NGC PyTorch base — see the audio/cluster rule for NGC torch-pinning caveats).