fix(perplexity): validate API keys via /v1/models endpoint

Perplexity deprecated the unversioned `/models` endpoint (now 404),
so the OpenAI-like key validator (validateOpenAILikeProvider in
src/lib/providers/validation.ts) would derive `<baseUrl>/models`
via addModelsSuffix from the perplexity registry baseUrl and hit a
dead endpoint, misclassifying valid keys.

Pin an explicit `modelsUrl` on the perplexity registry entry so
validation probes `/v1/models` directly. The dashboard models
discovery route (src/app/api/providers/[id]/models/route.ts)
already tries `/v1/models` first via its endpoints fallback list,
so it is unaffected.

Co-authored-by: gaoliao1688 <gaoliao1688@users.noreply.github.com>
Inspired-by: https://github.com/decolua/9router/commit/db4499d6

open-sse/config/providers/registry/perplexity/index.ts

@@ -6,6 +6,11 @@ export const perplexityProvider: RegistryEntry = {
   format: "openai",
   executor: "default",
   baseUrl: "https://api.perplexity.ai/chat/completions",
+  // Perplexity deprecated the unversioned `/models` endpoint (returns 404), so
+  // pin an explicit `modelsUrl` here. Without it, validateOpenAILikeProvider
+  // (src/lib/providers/validation.ts) derives `<baseUrl>/models` via
+  // addModelsSuffix and probes the dead endpoint, misclassifying valid keys.
+  modelsUrl: "https://api.perplexity.ai/v1/models",
   authType: "apikey",
   authHeader: "bearer",
   models: [

tests/unit/perplexity-key-validation-models.test.ts

@@ -0,0 +1,50 @@
+// Regression test for perplexity API key validation.
+//
+// Perplexity deprecated the unversioned `/models` endpoint (returns 404), so
+// our default validation probe — which derives `<baseUrl>/models` from the
+// perplexity registry entry via `addModelsSuffix` — would always fail to
+// confirm a valid key, falling through to the chat-completions probe and
+// often misclassifying live keys as "Invalid". Inspired by upstream
+// 9router fix (see commit message); we port it OmniRoute-style by
+// declaring an explicit `modelsUrl` on the perplexity registry entry.
+
+import { describe, it } from "node:test";
+import assert from "node:assert";
+
+describe("perplexity registry — key validation models endpoint", () => {
+  it("declares a modelsUrl pointing at /v1/models (not the deprecated /models)", async () => {
+    const { getRegistryEntry } = await import(
+      "../../open-sse/config/providerRegistry.ts"
+    );
+    const entry = getRegistryEntry("perplexity");
+    assert.ok(entry, "perplexity must be registered in the execution registry");
+    assert.equal(entry.format, "openai");
+    assert.ok(
+      typeof entry.modelsUrl === "string" && entry.modelsUrl.length > 0,
+      "perplexity registry entry must declare an explicit modelsUrl so key " +
+        "validation does not hit the deprecated <baseUrl>/models endpoint"
+    );
+    assert.equal(
+      entry.modelsUrl,
+      "https://api.perplexity.ai/v1/models",
+      "perplexity modelsUrl must point at the versioned /v1/models endpoint " +
+        "(unversioned /models was deprecated and now returns 404)"
+    );
+  });
+
+  it("does not derive a /models URL that ends in /chat/completions/models", async () => {
+    const { getRegistryEntry } = await import(
+      "../../open-sse/config/providerRegistry.ts"
+    );
+    const entry = getRegistryEntry("perplexity");
+    assert.ok(entry?.modelsUrl, "modelsUrl required");
+    assert.ok(
+      !entry.modelsUrl.includes("/chat/completions"),
+      "modelsUrl must not include /chat/completions"
+    );
+    assert.ok(
+      entry.modelsUrl.endsWith("/v1/models"),
+      "modelsUrl must end with /v1/models"
+    );
+  });
+});