fix: remove Git LFS tracking for docs images so Mintlify can serve them (#446)

Mintlify deploys docs by cloning the repo but does not run `git lfs
pull`. The `.gitattributes` rule `docs/images/** filter=lfs` caused
all doc images to be stored as ~130-byte LFS pointer files, which
Mintlify served as-is — breaking every image on the site.

Removing the LFS rule and re-adding the files as regular git blobs
fixes all images without changing any paths or MDX files.

Also fixes broken Slack link placeholder in troubleshooting page.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: shadowfax92

.gitattributes

@@ -9,5 +9,4 @@ packages/browseros/chromium_patches/**/*.py linguist-generated
 scripts/*.py linguist-generated
 # Mark build directories as generated
 build/* linguist-generated
-docs/images/** filter=lfs diff=lfs merge=lfs -text
 docs/videos/** filter=lfs diff=lfs merge=lfs -text