[core] Convert GOWS Lottie stickers (application/was) to animated WebP - fix #2039 closes devlikeapro/waha-plus#43

Lottie stickers arrive from WhatsApp as a ZIP archive (mimetype
application/was) containing animation/animation.json. This change
intercepts those stickers in the GOWS Plus session, renders each
animation frame off-screen, and delivers an animated WebP to the
webhook instead of the raw ZIP.

Implementation:
- src/plus/utils/lottie-converter.ts (new):
  - Extracts animation.json from the ZIP via adm-zip
  - Renders frames with @lottiefiles/dotlottie-web + @napi-rs/canvas
    (HTMLCanvasElement polyfill required; ImageData must NOT be polyfilled
    to avoid per-frame pixel caching in WASM memory)
  - Drives frames manually via dotLottie.setFrame(i) after 'load' for
    reliable synchronous capture
  - Encodes each RGBA frame to single-frame WebP with sharp (quality=80)
  - Assembles animated WebP via node-webpmux with full alpha transparency
  - Frame delay derived from animation fps; clamped to >=30ms
  - Fallback delay configurable via WAHA_LOTTIE_DEFAULT_DELAY_MS env var
  - sharp/adm-zip/node-webpmux loaded via require() — their module.exports
    is the callable itself with no .default, so ESM default import resolves
    to undefined at runtime

- src/plus/engines/gows/session.gows.plus.ts:
  - Overrides downloadMedia with LottieAwareGOWSEngineMediaProcessor
  - normalizeStickerUrl: fixes GOWS URL field case mismatch (URL vs url)
    that caused an infinite network loop on Lottie downloads
  - Reports mimetype image/webp and extension .webp for Lottie stickers

- package.json: add @lottiefiles/dotlottie-web, @napi-rs/canvas,
  node-webpmux to dependencies

package.json

@@ -39,7 +39,9 @@
     "@casl/ability": "^6.8.0",
     "@figuro/chatwoot-sdk": "^1.1.17",
     "@liaoliaots/nestjs-redis": "^9",
+    "@lottiefiles/dotlottie-web": "^0.72.1",
     "@modelcontextprotocol/sdk": "^1.29.0",
+    "@napi-rs/canvas": "^1.0.0",
     "@nestjs/axios": "^3.0.2",
     "@nestjs/bullmq": "^11.0.2",
     "@nestjs/common": "^11.0.0",
@@ -94,6 +96,7 @@
     "mustache": "^4.2.0",
     "nestjs-pino": "^4.1.0",
     "node-cache": "5.1.2",
+    "node-webpmux": "^3.2.1",
     "passport": "^0.7.0",
     "passport-headerapikey": "^1.2.2",
     "pg": "^8.13.1",