test: reorganize flat test files into purpose-based subdirectories (phase 6)

Group 245 flat integration tests and 25 loose unit tests into
discoverable subdirectories per spec section 6:

  integration/tools/{image,video,audio,document,data}/  (156 files)
  integration/platform/                                  (64 files)
  integration/generated/                                 (14 files)
  integration/security/                                  (10 files)

  unit/security/     (8 files, new subdir)
  unit/api/          (7 files moved in)
  unit/web/          (3 files moved in)
  unit/shared/       (6 files moved in)
  unit/image-engine/ (1 file moved in)

All moves via git mv (history preserved). Relative imports repaired
for both depth levels (platform/generated/security = +1, tools/ = +2):
static from-imports, dynamic import() calls, vi.mock() paths,
import.meta.dirname joins, and __dirname joins.

Vitest discovery unchanged (no test.include in config, recursive glob
matches subdirs, shard-by-hash unaffected). test-server.ts and
tool-route-drift.test.ts stay at integration root. fixtures/ untouched.

Parity gate: 13189 passing test names before = 13189 after (0 dropped).

tests/integration/tools/audio/split-audio.test.ts

@@ -0,0 +1,130 @@
+import { ffmpegAvailable } from "@snapotter/media-engine";
+import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { fixtures, readFixture } from "../../../fixtures/index.js";
+import {
+  buildTestApp,
+  createMultipartPayload,
+  loginAsAdmin,
+  type TestApp,
+} from "../../test-server.js";
+
+const MP3 = readFixture(fixtures.audio.tiny("mp3"));
+const TONE_GAP = readFixture(fixtures.audio.gap);
+
+let testApp: TestApp;
+let adminToken: string;
+
+beforeAll(async () => {
+  testApp = await buildTestApp();
+  adminToken = await loginAsAdmin(testApp.app);
+}, 30_000);
+
+afterAll(async () => {
+  await testApp.cleanup();
+}, 10_000);
+
+describe.skipIf(!ffmpegAvailable())("split-audio (requires ffmpeg)", () => {
+  it("splits into 2 parts via parts mode", async () => {
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "tiny.mp3", contentType: "audio/mpeg", content: MP3 },
+      { name: "settings", content: JSON.stringify({ mode: "parts", parts: 2 }) },
+    ]);
+    const res = await testApp.app.inject({
+      method: "POST",
+      url: "/api/v1/tools/split-audio",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+    const envelope = JSON.parse(res.body);
+    expect(envelope.downloadUrl).toBeDefined();
+
+    const dl = await testApp.app.inject({ method: "GET", url: envelope.downloadUrl });
+    expect(dl.statusCode).toBe(200);
+    // ZIP magic: PK\x03\x04
+    expect(dl.rawPayload[0]).toBe(0x50);
+    expect(dl.rawPayload[1]).toBe(0x4b);
+  }, 60_000);
+
+  it("splits by silence on tone-gap.wav", async () => {
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "tone-gap.wav", contentType: "audio/wav", content: TONE_GAP },
+      {
+        name: "settings",
+        content: JSON.stringify({ mode: "silence", thresholdDb: -40, minSilenceS: 0.2 }),
+      },
+    ]);
+    const res = await testApp.app.inject({
+      method: "POST",
+      url: "/api/v1/tools/split-audio",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+    const envelope = JSON.parse(res.body);
+    const dl = await testApp.app.inject({ method: "GET", url: envelope.downloadUrl });
+    expect(dl.statusCode).toBe(200);
+    // ZIP magic
+    expect(dl.rawPayload[0]).toBe(0x50);
+    expect(dl.rawPayload[1]).toBe(0x4b);
+    expect(dl.rawPayload.length).toBeGreaterThan(400);
+  }, 60_000);
+
+  it("rejects silence mode when no silence found", async () => {
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "tiny.mp3", contentType: "audio/mpeg", content: MP3 },
+      {
+        name: "settings",
+        content: JSON.stringify({ mode: "silence", thresholdDb: -40, minSilenceS: 0.2 }),
+      },
+    ]);
+    const res = await testApp.app.inject({
+      method: "POST",
+      url: "/api/v1/tools/split-audio",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(422);
+    const parsed = JSON.parse(res.body);
+    expect(parsed.details).toMatch(/no silence found/i);
+  }, 60_000);
+
+  it("splits by time mode on tone-gap.wav (segmentS=1)", async () => {
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "tone-gap.wav", contentType: "audio/wav", content: TONE_GAP },
+      { name: "settings", content: JSON.stringify({ mode: "time", segmentS: 1 }) },
+    ]);
+    const res = await testApp.app.inject({
+      method: "POST",
+      url: "/api/v1/tools/split-audio",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(200);
+    const envelope = JSON.parse(res.body);
+    const dl = await testApp.app.inject({ method: "GET", url: envelope.downloadUrl });
+    expect(dl.statusCode).toBe(200);
+    // ZIP magic
+    expect(dl.rawPayload[0]).toBe(0x50);
+    expect(dl.rawPayload[1]).toBe(0x4b);
+  }, 60_000);
+
+  it("rejects parts=1 (schema minimum is 2)", async () => {
+    const { body, contentType } = createMultipartPayload([
+      { name: "file", filename: "tiny.mp3", contentType: "audio/mpeg", content: MP3 },
+      { name: "settings", content: JSON.stringify({ mode: "parts", parts: 1 }) },
+    ]);
+    const res = await testApp.app.inject({
+      method: "POST",
+      url: "/api/v1/tools/split-audio",
+      headers: { authorization: `Bearer ${adminToken}`, "content-type": contentType },
+      body,
+    });
+
+    expect(res.statusCode).toBe(400);
+  }, 60_000);
+});