fix: three correctness bugs found in review + a dropped-log

fail() blanket-marked the instance `failed` for every dead-lettered task kind.
Only provision is correct. The others each left the instance in a state the
UPDATE then corrupted:
  - deprovision: `deleting` -> `failed` stranded the instance, because
    due_for_deprovision only re-selects ready/deleting, leaking the release
    reconcile.py promises to reclaim.
  - upgrade: helm --atomic rolled back, so the instance was still `ready` and
    serving the old version; `failed` mislabelled a healthy service and dropped
    it off the upgrade work-list.
  - verify: handle_verify already halted the rollout; the instance was `ready`.
Now gated on kind == provision, with a regression test per kind (control-tested
against the blanket UPDATE, which fails all three).

The API exception handler was registered on fastapi.HTTPException, a subclass
of starlette's. Starlette matches handlers by walking type(exc).__mro__, so
framework-raised 404/405 never hit it and returned {"detail": ...} instead of
ErrorBody. Registered on the starlette parent, and added a
RequestValidationError handler so body-validation 422s share the shape too.
Tests assert the ErrorBody shape for framework 404, 405, and a forbidden field.

helm._list_releases_via_api built the httpx client with verify=<ca path>, which
loads the CA eagerly and raises OSError on a half-mounted ServiceAccount — an
error the except clause did not catch, crashing the reconciler tick as a bare
bug. Now the CA is checked for readability alongside the token, and a missing
one means "not in-cluster" and falls back to helm. Also documents the no-limit
pagination invariant and pins it with a test.

redis.py logged through stdlib logging with extra={"team": team}, which the
structlog bridge drops on the floor — the trap notify.py documents. Switched to
a bound logger with team as a kwarg.

tests/integration/test_api.py

@@ -298,6 +298,46 @@ async def test_ttl_out_of_range_is_422(client: httpx.AsyncClient, token: str) ->
     assert resp.status_code == 422
 
 
+def _is_error_body(payload: object) -> bool:
+    """The uniform error shape: a dict with `code` and `message`, and no default `detail`."""
+    return isinstance(payload, dict) and "code" in payload and "message" in payload
+
+
+async def test_framework_404_uses_the_error_body_shape(client: httpx.AsyncClient) -> None:
+    """A 404 raised by the router, not a handler, must still be ErrorBody.
+
+    Starlette raises its own HTTPException for an unknown route. The exception handler is
+    registered on that parent class precisely so this body is ErrorBody and not FastAPI's
+    default `{"detail": "Not Found"}` — one shape for every error.
+    """
+    resp = await client.get("/v1/no-such-route")
+    assert resp.status_code == 404
+    assert _is_error_body(resp.json()), resp.text
+
+
+async def test_framework_405_uses_the_error_body_shape(client: httpx.AsyncClient) -> None:
+    """A wrong-method 405 comes from the router too, and must be ErrorBody."""
+    resp = await client.delete("/v1/instances")  # collection route has no DELETE
+    assert resp.status_code == 405
+    assert _is_error_body(resp.json()), resp.text
+
+
+async def test_body_validation_422_uses_the_error_body_shape(client: httpx.AsyncClient, token: str) -> None:
+    """A RequestValidationError 422 must match the handler-raised 422 shape.
+
+    A forbidden extra field trips pydantic's `extra="forbid"` and raises
+    RequestValidationError, which the dedicated handler renders as ErrorBody rather than the
+    default `{"detail": [...]}`.
+    """
+    resp = await client.post(
+        "/v1/instances",
+        headers=auth(token),
+        json={"service_type": "redis", "size": "small", "surprise": "field"},
+    )
+    assert resp.status_code == 422
+    assert _is_error_body(resp.json()), resp.text
+
+
 # --------------------------------------------------------------------------- authn