fix(connectors): guard pi provider resolution

tests/unit/connector-provider-guard.test.ts

@@ -0,0 +1,56 @@
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import { getProviders } from "@mariozechner/pi-ai";
+import { describe, expect, it } from "vitest";
+import {
+  CONNECTORS,
+  getConnectorKnownProvider,
+  getConnectorProvider,
+  isLocalModelResolverProvider,
+  isPiKnownProvider,
+} from "../../src/main/connectors";
+import { FIREWORKS_FIREPASS_MODEL_ID, resolveModel, resolveModels } from "../../src/main/model-resolver";
+
+describe("connector provider guard", () => {
+  it("classifies catalog providers before they enter pi-ai APIs", () => {
+    const piProviders = new Set(getProviders());
+
+    for (const connector of CONNECTORS) {
+      const provider = getConnectorProvider(connector.id);
+      expect(provider).toBe(connector.provider);
+
+      if (isLocalModelResolverProvider(provider)) {
+        expect(getConnectorKnownProvider(connector.id)).toBeNull();
+      } else {
+        expect(isPiKnownProvider(provider)).toBe(true);
+        expect(piProviders.has(provider)).toBe(true);
+        expect(getConnectorKnownProvider(connector.id)).toBe(provider);
+      }
+    }
+  });
+
+  it("uses the provider guard in model discovery", () => {
+    const anthropicModels = resolveModels("anthropic");
+    const firstAnthropicModel = anthropicModels[0];
+    if (!firstAnthropicModel) throw new Error("Anthropic model catalog is empty.");
+
+    expect(resolveModel("anthropic", firstAnthropicModel.id)?.id).toBe(firstAnthropicModel.id);
+    expect(resolveModels("not-a-pi-provider")).toEqual([]);
+    expect(resolveModel("not-a-pi-provider", "model-id")).toBeNull();
+    expect(resolveModel("fireworks-firepass", "ignored")?.id).toBe(FIREWORKS_FIREPASS_MODEL_ID);
+  });
+
+  it("keeps provider calls free of erased never casts", () => {
+    const files = [
+      "src/main/model-resolver.ts",
+      "src/main/connector-health-service.ts",
+      "src/main/credentials/credential-resolver.ts",
+    ];
+
+    for (const file of files) {
+      const source = readFileSync(join(process.cwd(), file), "utf8");
+      expect(source).not.toContain("provider as never");
+      expect(source).not.toContain("definition.provider as never");
+    }
+  });
+});