perf: switch to domcontentloaded default, optimize browser pool, fix swagger paths

Performance fixes:
- Default waitUntil changed from networkidle2 to domcontentloaded (saves ~500ms+)
- Add waitUntil parameter so users can choose (load/domcontentloaded/networkidle0/networkidle2)
- Optimize page recycle: use DOM reset instead of about:blank navigation
- Add Chromium flags to disable unnecessary features (background networking, extensions, sync, etc.)

Swagger fixes:
- Fix apis glob to include dist/*.js (was only matching src/*.ts, empty at runtime)
- Document new waitUntil parameter on POST /v1/screenshot
- Add OpenAPI docs for /status endpoint

src/routes/screenshot.ts

@@ -70,6 +70,14 @@ export const screenshotRouter = Router();
  *                 maximum: 5000
  *                 default: 0
  *                 description: Extra delay in ms after page load before capturing
+ *               waitUntil:
+ *                 type: string
+ *                 enum: [load, domcontentloaded, networkidle0, networkidle2]
+ *                 default: domcontentloaded
+ *                 description: >
+ *                   Page load event to wait for before capturing.
+ *                   "domcontentloaded" (default) is fastest for most pages.
+ *                   Use "networkidle2" for JS-heavy SPAs that load data after initial render.
  *           examples:
  *             simple:
  *               summary: Simple screenshot
@@ -122,7 +130,7 @@ export const screenshotRouter = Router();
  *             schema: { $ref: "#/components/schemas/Error" }
  */
 screenshotRouter.post("/", async (req: any, res) => {
-  const { url, format, width, height, fullPage, quality, waitForSelector, deviceScale, delay } = req.body;
+  const { url, format, width, height, fullPage, quality, waitForSelector, deviceScale, delay, waitUntil } = req.body;
 
   if (!url || typeof url !== "string") {
     res.status(400).json({ error: "Missing required parameter: url" });
@@ -140,6 +148,7 @@ screenshotRouter.post("/", async (req: any, res) => {
       waitForSelector,
       deviceScale: deviceScale ? parseFloat(deviceScale) : undefined,
       delay: delay ? parseInt(delay, 10) : undefined,
+      waitUntil: ["load", "domcontentloaded", "networkidle0", "networkidle2"].includes(waitUntil) ? waitUntil : undefined,
     });
 
     res.setHeader("Content-Type", result.contentType);