fix(gfx): wire up WebRender gradient dithering

feat(blocker): part 3 - offline filter list assets

feat(blocker): part 3 - offline filter list assets

feat(webcompat): add mimic_Firefox_UA intervention for discord.com

fix: bypass Darwin x86_64 asm atomics with compiler builtins

Switch Darwin x86_64 NSPR atomics to __sync_* builtins to avoid missing PR_Darwin_x86_64_* symbols in CI. This trades the asm implementation for portable compiler atomics on x86_64.

feat(tab features): allow hiding duplicate tab context menu option

temp: macOS runner issue workaround

fix: cookie banner silence console error logs

backport: bug 1970223 - python3.14 support

backport: bug 1970223 - python3.14 support