chore: deploy to Cloudflare Pages and update branding

- Add Cloudflare Pages deployment for landing page (snapotter.com) and
  docs (docs.snapotter.com)
- Create deploy-landing.yml and update deploy-docs.yml workflows
- Update CI to ignore apps/landing/** paths
- Fix logo transparency (remove white background) across all apps
- Recreate social-preview.png with SnapOtter branding
- Update all docs URLs from GitHub Pages to docs.snapotter.com
- Update VitePress config: light theme default, fix llms.txt paths
- Add .vitepress/cache/ and .env.* to gitignore

packages/ai/python/gpu.py

@@ -15,7 +15,7 @@ def emit_info(msg):
 def gpu_available():
     """Return True if a usable CUDA GPU is present at runtime."""
     # Allow explicit disable via env var (set to "false" or "0")
-    override = os.environ.get("ASHIM_GPU")
+    override = os.environ.get("SNAPOTTER_GPU")
     if override is not None and override.lower() in ("0", "false", "no"):
         return False