Add .git-blame-ignore-revs for bulk formatting/restructure commits

Tells git blame to skip past the ruff formatting (#2882) and app
restructure (#2883) commits so blame shows the actual author of each
line.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: JacobCoffee

.git-blame-ignore-revs

@@ -0,0 +1,5 @@
+# Ruff linting and formatting (#2882)
+2cf268f0c3b35973cfb6d5bbcfec5de09954eae7
+
+# Move apps under apps/ namespace and update all imports (#2883)
+31bc7e3698333333397292dc01d88e61e41761ab