fix: resolve 18 QA-discovered bugs across tools, previews, and the AI pipeline (#242)

Exhaustive QA sweep of all 157 tools. Fixes: CSP blob media, csv-excel ExcelJS interop, ocr-pdf segfault, chart-maker upload, non-PDF doc preview, RAW decode, merge-tool multi-file path, html-to-image chromium, ogv/wma/amr/ac3 preview fallbacks, meme/gif/stabilize codecs, nav+home a11y. Plus orphan-format and test-debt cleanup, the AI bundle build script, and a reusable Playwright QA harness under tests/qa/.

tests/qa/playwright.qa.config.ts

@@ -0,0 +1,45 @@
+import path from "node:path";
+import { defineConfig, devices } from "@playwright/test";
+
+// QA sweep config: drives the isolated QA Docker container (auth off) with REAL
+// Google Chrome (channel "chrome") so proprietary codecs (H.264/AAC/MP3) decode
+// and media previews are valid. No webServer: the container is external.
+//
+//   docker compose -f tests/qa/docker-compose.qa.yml up -d
+//   pnpm playwright test --config tests/qa/playwright.qa.config.ts
+
+const QA_BASE_URL = process.env.QA_BASE_URL || "http://localhost:13499";
+const repoRoot = path.join(__dirname, "..", "..");
+
+export default defineConfig({
+  testDir: ".",
+  testMatch: /.*\.qa\.spec\.ts$/,
+  // Generous default; long/AI specs raise their own via test.setTimeout().
+  timeout: 120_000,
+  expect: { timeout: 15_000 },
+  fullyParallel: true,
+  forbidOnly: !!process.env.CI,
+  retries: process.env.QA_RETRIES ? Number(process.env.QA_RETRIES) : 0,
+  // Conservative: the same machine runs the container doing FFmpeg/LibreOffice/AI.
+  workers: process.env.QA_WORKERS ? Number(process.env.QA_WORKERS) : 4,
+  reporter: [
+    ["list"],
+    ["json", { outputFile: path.join(repoRoot, "docs", "qa", "results.json") }],
+    ["html", { open: "never", outputFolder: path.join(repoRoot, "test-results", "qa-report") }],
+  ],
+  outputDir: path.join(repoRoot, "test-results", "qa-artifacts"),
+  use: {
+    baseURL: QA_BASE_URL,
+    screenshot: "only-on-failure",
+    trace: "retain-on-failure",
+    video: "off",
+    actionTimeout: 20_000,
+    navigationTimeout: 30_000,
+  },
+  projects: [
+    {
+      name: "qa-chrome",
+      use: { ...devices["Desktop Chrome"], channel: "chrome" },
+    },
+  ],
+});