fix(qwen): gadfly round 1 — three real findings, all sibling drift

The pre-flight comment was the worst of them, and three models agreed. It said
providers absent from the table "need no key or carry it in their endpoint/DSN"
— false for google, which needs a key and is absent for an entirely different
reason: it accepts GOOGLE_API_KEY *or* GEMINI_API_KEY, so a single-variable arm
would silently skip a correctly-configured reviewer. That reasoning was in the
PR description and not in the code, so the comment invited exactly the wrong
edit. It now states both exclusion reasons and names google's.

Forwarded KIMI_API_KEY alongside QWEN_API_KEY in the dogfooding stub. This PR
argues that sibling call sites must move together, and I declared both secrets
in the reusable workflow and forwarded one — a config that looks complete and
401s on the model you didn't wire.

The two endpoint-provider error messages listed the same accepted set in
different order and spelling. Both functions accept an identical set, so they
now share one endpointProviderNames constant and cannot disagree.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

cmd/gadfly/model.go

@@ -19,6 +19,13 @@ import (
 // model list is just ids like "qwen3-coder:480b-cloud" — working unchanged.
 const defaultProvider = "ollama-cloud"
 
+// endpointProviderNames is the operator-facing list of providers that accept an
+// explicit endpoint. resolveModel and endpointProvider accept the SAME set, so
+// they share one message rather than each carrying a hand-maintained copy that
+// drifts in order and spelling — which is exactly what happened when kimi/qwen
+// were added to both switches.
+const endpointProviderNames = "openai/openai-compatible/kimi/qwen/ollama/ollama-cloud/llama-swap(s)/foreman/anthropic/google"
+
 // resolveModel builds the review model from the environment. Gadfly is powered
 // by majordomo, so it can target any provider majordomo supports — Ollama
 // (local or cloud), OpenAI, Anthropic, Google, or any OpenAI/Ollama-compatible
@@ -115,7 +122,7 @@ func resolveModel() (llm.Model, error) {
 		}
 		return google.New(opts...).Model(model)
 	default:
-		return nil, fmt.Errorf("GADFLY_BASE_URL is set but GADFLY_PROVIDER %q has no endpoint-override support (use openai/openai-compatible/kimi/qwen/ollama/llama-swap/foreman/anthropic/google, or unset GADFLY_BASE_URL to resolve via majordomo)", provider)
+		return nil, fmt.Errorf("GADFLY_BASE_URL is set but GADFLY_PROVIDER %q has no endpoint-override support (use %s, or unset GADFLY_BASE_URL to resolve via majordomo)", provider, endpointProviderNames)
 	}
 }
 
@@ -288,6 +295,6 @@ func endpointProvider(name, raw string) (llm.Provider, error) {
 		}
 		return google.New(opts...), nil
 	default:
-		return nil, fmt.Errorf("unknown provider %q (use ollama/llama-swap(s)/foreman/openai/openai-compatible/kimi/qwen/anthropic/google)", provider)
+		return nil, fmt.Errorf("unknown provider %q (use %s)", provider, endpointProviderNames)
 	}
 }