fix(deepgram): revert to /v1/auth/grant for temporary JWT tokens

- /v1/projects/{id}/keys creates permanent API keys, not WebSocket-compatible JWT tokens
- /v1/auth/grant requires Member-scoped API key (now configured)
- Remove DEEPGRAM_PROJECT_ID dependency
- Update tests

Typecheck: OK · Tests: 241/241 ✅

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/routes/__tests__/transcriptionsToken.test.ts

@@ -33,7 +33,6 @@ const JSON_HEADERS = {
 describe("POST /transcriptions/token — Sprint 4b", () => {
   beforeEach(() => {
     vi.restoreAllMocks();
-    process.env.DEEPGRAM_PROJECT_ID = "proj-test-123";
   });
 
   it("401 sans Authorization", async () => {
@@ -48,8 +47,8 @@ describe("POST /transcriptions/token — Sprint 4b", () => {
       vi.fn().mockResolvedValue({
         ok: true,
         json: async () => ({
-          key: "dg-temp-abc123",
-          api_key_id: "id-1",
+          access_token: "dg-temp-abc123",
+          expires_in: 600,
         }),
       }),
     );
@@ -66,10 +65,10 @@ describe("POST /transcriptions/token — Sprint 4b", () => {
     expect(body.expires_in).toBe(600);
   });
 
-  it("appelle POST /v1/projects/{id}/keys avec Authorization Token <key> et le bon body", async () => {
+  it("appelle POST /v1/auth/grant avec Authorization Token <key> et ttl_seconds=600", async () => {
     const fetchMock = vi.fn().mockResolvedValue({
       ok: true,
-      json: async () => ({ key: "tok" }),
+      json: async () => ({ access_token: "tok" }),
     });
     vi.stubGlobal("fetch", fetchMock);
 
@@ -81,16 +80,10 @@ describe("POST /transcriptions/token — Sprint 4b", () => {
 
     expect(fetchMock).toHaveBeenCalledTimes(1);
     const [url, init] = fetchMock.mock.calls[0];
-    expect(String(url)).toBe(
-      "https://api.deepgram.com/v1/projects/proj-test-123/keys",
-    );
+    expect(String(url)).toBe("https://api.deepgram.com/v1/auth/grant");
     const headers = (init?.headers ?? {}) as Record<string, string>;
     expect(headers["Authorization"]).toMatch(/^Token /);
-    expect(JSON.parse(init.body as string)).toEqual({
-      comment: "expria-temp",
-      scopes: ["usage:write"],
-      time_to_live_in_seconds: 600,
-    });
+    expect(JSON.parse(init.body as string)).toEqual({ ttl_seconds: 600 });
   });
 
   it("500 INTERNAL_ERROR si Deepgram non-OK", async () => {
@@ -129,12 +122,12 @@ describe("POST /transcriptions/token — Sprint 4b", () => {
     expect(res.status).toBe(500);
   });
 
-  it("500 INTERNAL_ERROR si key absent dans la réponse Deepgram", async () => {
+  it("500 INTERNAL_ERROR si access_token absent dans la réponse Deepgram", async () => {
     vi.stubGlobal(
       "fetch",
       vi.fn().mockResolvedValue({
         ok: true,
-        json: async () => ({ api_key_id: "id-1" }),
+        json: async () => ({ expires_in: 600 }),
       }),
     );