Add .git-blame-ignore-revs for cleaner git blame (#5078)

- Created .git-blame-ignore-revs file to exclude mass formatting commits
- Added automatic git config in package.json prepare script
- Excluded litegraph migration formatting commit (10k+ line changes)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

package.json

@@ -19,7 +19,7 @@
     "test:browser": "npx playwright test",
     "test:unit": "vitest run tests-ui/tests",
     "test:component": "vitest run src/components/",
-    "prepare": "husky || true",
+    "prepare": "husky || true && git config blame.ignoreRevsFile .git-blame-ignore-revs || true",
     "preview": "vite preview",
     "lint": "eslint src --cache",
     "lint:fix": "eslint src --cache --fix",