feat(streamer): chromium cdp screencast driver

streamer/src/chrome.ts

@@ -0,0 +1,60 @@
+import { EventEmitter } from "node:events";
+import puppeteer, { Browser, CDPSession, Page } from "puppeteer-core";
+
+export interface ChromeOpts {
+  pageUrl: string;
+  width: number;
+  height: number;
+  framerate: number;
+  jpegQuality?: number;          // 0..100, default 85
+  executablePath?: string;       // default /usr/bin/chromium
+}
+
+export class ChromeRenderer extends EventEmitter {
+  private browser: Browser | null = null;
+  private page: Page | null = null;
+  private cdp: CDPSession | null = null;
+
+  constructor(private opts: ChromeOpts) { super(); }
+
+  async start(): Promise<void> {
+    this.browser = await puppeteer.launch({
+      executablePath: this.opts.executablePath ?? "/usr/bin/chromium",
+      headless: true,
+      args: [
+        "--no-sandbox",
+        "--disable-dev-shm-usage",
+        "--disable-gpu",
+        "--hide-scrollbars",
+        `--window-size=${this.opts.width},${this.opts.height}`,
+        "--autoplay-policy=no-user-gesture-required",
+      ],
+      defaultViewport: { width: this.opts.width, height: this.opts.height },
+    });
+    this.page = await this.browser.newPage();
+    await this.page.goto(this.opts.pageUrl, { waitUntil: "networkidle2" });
+
+    this.cdp = await this.page.target().createCDPSession();
+    await this.cdp.send("Page.startScreencast", {
+      format: "jpeg",
+      quality: this.opts.jpegQuality ?? 85,
+      everyNthFrame: 1,
+    });
+
+    this.cdp.on("Page.screencastFrame", async (frame) => {
+      const buf = Buffer.from(frame.data, "base64");
+      this.emit("frame", buf);
+      await this.cdp!.send("Page.screencastFrameAck", { sessionId: frame.sessionId });
+    });
+
+    this.browser.on("disconnected", () => this.emit("disconnected"));
+  }
+
+  async stop(): Promise<void> {
+    try { await this.cdp?.send("Page.stopScreencast"); } catch { /* ignore */ }
+    await this.browser?.close().catch(() => {});
+    this.browser = null;
+    this.page = null;
+    this.cdp = null;
+  }
+}