fix(selfbot): smooth VNC capture via keepalive + stop ffmpeg leak on stream end

The Go-Live broadcast looked badly choppy: video and scrolling stuttered while
the cursor stayed smooth. Root cause is TigerVNC: it only refreshes its
framebuffer while a VNC client is attached, but the broadcast reads that
framebuffer with x11grab (not as a VNC client). With no viewer attached the
captured screen idled at ~1.5 fps (measured 3/30 distinct frames); the cursor
looked smooth only because x11grab overlays the live cursor on every frame.

- Add a headless RFB keepalive (vnc-keepalive.ts) that stays connected for the
  life of the stream and requests incremental framebuffer updates at the stream
  framerate. SelfbotStreamer starts it on broadcast start and tears it down on
  stop/self-end. Measured 3/30 -> 57/60 distinct frames at 60 fps. Fail-open;
  authenticates with VNC_PASSWORD or the ~/.config/tigervnc/passwd file.
- Fix a resource leak: when the Go-Live ended on its own, only the active flag
  was cleared, leaving the x11grab->nvenc ffmpeg running forever (pinning a CPU
  core while no media was transmitted, with only the gateway TCP left and no UDP
  media). The self-end path now tears down capture, keepalive and voice like
  stop() does.
- Tests for both paths (self-end teardown; keepalive DES auth, port mapping,
  password resolution). Add @types/bun so bun:test typechecks; document the
  keepalive and recommended Chrome flags in README and .env.example.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

bot/bun.lock

@@ -14,6 +14,7 @@
         "qrcode": "^1.5.4",
       },
       "devDependencies": {
+        "@types/bun": "^1.3.14",
         "@types/node": "^22.7.0",
         "@types/qrcode": "^1.5.6",
         "typescript": "^5.6.3",
@@ -211,6 +212,8 @@
 
     "@tybys/wasm-util": ["@tybys/wasm-util@0.10.2", "", { "dependencies": { "tslib": "^2.4.0" } }, "sha512-RoBvJ2X0wuKlWFIjrwffGw1IqZHKQqzIchKaadZZfnNpsAYp2mM0h36JtPCjNDAHGgYez/15uMBpfGwchhiMgg=="],
 
+    "@types/bun": ["@types/bun@1.3.14", "", { "dependencies": { "bun-types": "1.3.14" } }, "sha512-h1hFqFVcvAvD9j9K7ZW7vd82aSA+rTdznZa+5bwvCwqSB1jmmfLcbIWhOLx1/+boy/xmjgCs/OMUL8hRJSmnPw=="],
+
     "@types/node": ["@types/node@22.19.20", "", { "dependencies": { "undici-types": "~6.21.0" } }, "sha512-6tELRwSDYWW9EdZhbeZmYGZ1/7Djkt+Ah3/ScEYT9cDord7UJzasR/4D3VONg9tQI5CDp+/CZC1AXj2pCFOvpw=="],
 
     "@types/qrcode": ["@types/qrcode@1.5.6", "", { "dependencies": { "@types/node": "*" } }, "sha512-te7NQcV2BOvdj2b1hCAHzAoMNuj65kNBMz0KBaxM6c3VGBOhU0dURQKOtH8CFNI/dsKkwlv32p26qYQTWoB5bw=="],
@@ -243,6 +246,8 @@
 
     "buffer-crc32": ["buffer-crc32@1.0.0", "", {}, "sha512-Db1SbgBS/fg/392AblrMJk97KggmvYhr4pB5ZIMTWtaivCPMWLkmb7m21cJvpvgK+J3nsU2CmmixNBZx4vFj/w=="],
 
+    "bun-types": ["bun-types@1.3.14", "", { "dependencies": { "@types/node": "*" } }, "sha512-4N0ig0fEomHt5R0KCFWjovxow98rIoRwKolrYdCcknNwMekCXRnWEUvgu5soYV8QXtVsrUD8B95MBOZGPvr6KQ=="],
+
     "camelcase": ["camelcase@5.3.1", "", {}, "sha512-L28STB170nwWS63UjtlEOE3dldQApaJXZkOI1uMFfzf3rRuPegHaHesyee+YxQ+W6SvRDQV6UrdOdRiR153wJg=="],
 
     "chalk": ["chalk@4.1.2", "", { "dependencies": { "ansi-styles": "^4.1.0", "supports-color": "^7.1.0" } }, "sha512-oKnbhFyRIXpUuez8iBMmyEa4nbj4IOQyuhc/wy9kY7/WVPcwIO9VA668Pu8RkO7+0G76SLROeyw9CpQ061i4mA=="],