feat(eo): restore audioBase64 mode for Gemini batch transcription

- POST /corrections/eo accepts audioBase64 + mimeType (XOR with transcript)
- Gemini transcribeAudio called server-side before correction
- No audio storage (client downloads locally)
- /transcriptions/token kept for future Deepgram live use

Typecheck: OK · Tests: all green

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

src/routes/__tests__/correctionsEO.test.ts

@@ -73,7 +73,7 @@ describe("POST /corrections/eo — Sprint 4a", () => {
     expect(res.status).toBe(400);
   });
 
-  it("400 si transcript manquant", async () => {
+  it("400 si ni transcript ni audioBase64 fournis", async () => {
     const app = buildApp();
     const res = await app.request("/corrections/eo", {
       method: "POST",
@@ -85,6 +85,36 @@ describe("POST /corrections/eo — Sprint 4a", () => {
     expect(body.code).toBe("VALIDATION_ERROR");
   });
 
+  it("400 si transcript ET audioBase64 fournis simultanément (XOR)", async () => {
+    const app = buildApp();
+    const res = await app.request("/corrections/eo", {
+      method: "POST",
+      headers: JSON_HEADERS,
+      body: JSON.stringify({
+        simulationId: "s1",
+        tache: "EO_T1",
+        transcript: "t",
+        audioBase64: "AAAA",
+        mimeType: "audio/webm",
+      }),
+    });
+    expect(res.status).toBe(400);
+  });
+
+  it("400 si audioBase64 sans mimeType", async () => {
+    const app = buildApp();
+    const res = await app.request("/corrections/eo", {
+      method: "POST",
+      headers: JSON_HEADERS,
+      body: JSON.stringify({
+        simulationId: "s1",
+        tache: "EO_T1",
+        audioBase64: "AAAA",
+      }),
+    });
+    expect(res.status).toBe(400);
+  });
+
   it("400 si nclc_cible invalide", async () => {
     const app = buildApp();
     const res = await app.request("/corrections/eo", {
@@ -133,6 +163,34 @@ describe("POST /corrections/eo — Sprint 4a", () => {
     );
   });
 
+  it("200 mode batch audio (transmet audioBase64 + mimeType au controller)", async () => {
+    correctEOMock.mockResolvedValue({
+      data: { score: 14, nclc: 9, simulation_id: "s-audio", diagnostic: "d" },
+    });
+    const app = buildApp();
+    const res = await app.request("/corrections/eo", {
+      method: "POST",
+      headers: JSON_HEADERS,
+      body: JSON.stringify({
+        simulationId: "s-audio",
+        tache: "EO_T1",
+        audioBase64: "AAAA",
+        mimeType: "audio/webm",
+      }),
+    });
+    expect(res.status).toBe(200);
+    expect(correctEOMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        simulationId: "s-audio",
+        tache: "EO_T1",
+        nclcCible: 9,
+        audioBase64: "AAAA",
+        mimeType: "audio/webm",
+      }),
+      expect.any(Object),
+    );
+  });
+
   it("200 avec nclc_cible=10 transmis au controller", async () => {
     correctEOMock.mockResolvedValue({
       data: { score: 16, nclc: 10, simulation_id: "s2", diagnostic: "d" },

src/routes/corrections.ts

@@ -91,15 +91,19 @@ corrections.post("/ee", authMiddleware, async (c) => {
   return c.json(result.data, 200);
 });
 
-// Sprint 4b — POST /corrections/eo reçoit uniquement le transcript final.
-// La transcription live est gérée navigateur ↔ Deepgram (cf. /transcriptions/token).
-// Aucun audio n'est stocké côté backend.
+// Sprint 4b.2 — POST /corrections/eo accepte SOIT un transcript texte
+// SOIT un audio base64 + mimeType (transcrit côté backend via Gemini).
+// Aucun audio n'est stocké côté serveur ; le client garde une copie locale.
+const MAX_AUDIO_BASE64_LEN = 14 * 1024 * 1024;
+
 corrections.post("/eo", authMiddleware, async (c) => {
   let body: {
     simulationId?: unknown;
     transcript?: unknown;
     tache?: unknown;
     nclc_cible?: unknown;
+    audioBase64?: unknown;
+    mimeType?: unknown;
   };
   try {
     body = await c.req.json();
@@ -125,17 +129,6 @@ corrections.post("/eo", authMiddleware, async (c) => {
     );
   }
 
-  if (!body.transcript || typeof body.transcript !== "string") {
-    return c.json(
-      {
-        error: true,
-        code: "VALIDATION_ERROR",
-        message: "transcript est requis.",
-      },
-      400,
-    );
-  }
-
   if (!body.tache || !VALID_TACHES_EO.includes(body.tache as string)) {
     return c.json(
       {
@@ -147,6 +140,46 @@ corrections.post("/eo", authMiddleware, async (c) => {
     );
   }
 
+  // XOR : transcript OU (audioBase64 + mimeType). Pas les deux, pas aucun.
+  const hasTranscript =
+    typeof body.transcript === "string" && body.transcript.length > 0;
+  const hasAudio =
+    typeof body.audioBase64 === "string" && body.audioBase64.length > 0;
+  if (hasTranscript === hasAudio) {
+    return c.json(
+      {
+        error: true,
+        code: "VALIDATION_ERROR",
+        message:
+          "Fournir exactement un des deux : `transcript` (texte) ou `audioBase64` + `mimeType` (audio).",
+      },
+      400,
+    );
+  }
+
+  if (hasAudio) {
+    if (typeof body.mimeType !== "string" || body.mimeType.length === 0) {
+      return c.json(
+        {
+          error: true,
+          code: "VALIDATION_ERROR",
+          message: "`mimeType` est requis quand `audioBase64` est fourni.",
+        },
+        400,
+      );
+    }
+    if ((body.audioBase64 as string).length > MAX_AUDIO_BASE64_LEN) {
+      return c.json(
+        {
+          error: true,
+          code: "VALIDATION_ERROR",
+          message: "Audio trop volumineux (max ~10 Mo).",
+        },
+        413,
+      );
+    }
+  }
+
   // nclc_cible optionnel (défaut 9, valeurs 9 ou 10).
   let nclcCible: 9 | 10 = 9;
   if (body.nclc_cible !== undefined) {
@@ -169,13 +202,15 @@ corrections.post("/eo", authMiddleware, async (c) => {
       simulationId: body.simulationId,
       tache: body.tache as "EO_T1" | "EO_T3",
       nclcCible,
-      transcript: body.transcript,
+      transcript: hasTranscript ? (body.transcript as string) : undefined,
+      audioBase64: hasAudio ? (body.audioBase64 as string) : undefined,
+      mimeType: hasAudio ? (body.mimeType as string) : undefined,
     },
     profile,
   );
 
   if ("error" in result) {
-    return c.json(result, result.status as 401 | 404 | 500);
+    return c.json(result, result.status as 400 | 401 | 404 | 500);
   }
 
   return c.json(result.data, 200);