Placement now has many moving parts (image, weights, adapters, auth,
budgets, staging) and most of them fail minutes into a pod boot, in a log
nobody is watching. POST /v1/models/test runs the smallest real request
for the model's kind and reports what happened, with a Test run button on
every model page.

It dispatches THROUGH THE FRONT, so it exercises the same routing, auth,
pod provisioning and staging a real request would — a test that simulated
the path would prove nothing about the path.

`where` forces placement for that one request via a new x-coderai-placement
header the gateway honours: "local" ignores any remote configuration,
"remote" refuses to fall back to local. Without that you cannot verify a
pod at all: the request would be served wherever the config decided, and
a green result would mean nothing.

Kinds with no cheap synthetic input — video (minutes of GPU and real
money), faceswap, STT, OCR — report a reachability check and say plainly
that no generation was run, instead of implying more than was proven.

Also fixed test pollution I had introduced: the gateway fixture replaced
module-level functions without restoring them, and one test assigned
_model_entry_for unscoped. Both leaked into later tests, which passed
alone and failed in the suite — the failure mode that teaches you to
distrust the suite. Verified stable across repeated runs.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0182DhR1eFNPQyGmDrpHbedY