Fix ESLint issues across codebase

- Replace 'any' types with proper TypeScript interfaces
- Fix unescaped apostrophe in not-found page
- Convert actionTypes constant to type definition to fix unused variable
- Optimize font loading using next/font instead of external links
- Improve type safety and remove linting warnings

.eslintrc.json

@@ -0,0 +1,6 @@
+{
+  "extends": [
+    "next/core-web-vitals",
+    "next/typescript"
+  ]
+}