refactor: replace Google Fonts with FontSource packages and migrate to cn utility

- Replace Google Fonts CDN with self-hosted FontSource packages
- Add @fontsource-variable/inter for variable Inter font
- Add @fontsource/ibm-plex-mono with weight 400 for monospace font
- Create src/lib/utils.ts with shadcn's cn utility function
- Install tailwind-merge for intelligent Tailwind class merging
- Replace all clsx usages with cn utility across components
  - LookupInput.tsx: 7 replacements
  - ErrorCard.tsx: 1 replacement
  - Property.tsx: 2 replacements
- Remove Google Fonts URL import from globals.css

pnpm-lock.yaml

@@ -8,6 +8,12 @@ importers:
 
   .:
     dependencies:
+      '@fontsource-variable/inter':
+        specifier: ^5.2.8
+        version: 5.2.8
+      '@fontsource/ibm-plex-mono':
+        specifier: ^5.2.7
+        version: 5.2.7
       '@headlessui/react':
         specifier: ^2.2.9
         version: 2.2.9(react-dom@19.2.0(react@19.2.0))(react@19.2.0)
@@ -44,6 +50,9 @@ importers:
       sass:
         specifier: ^1.57.1
         version: 1.93.2
+      tailwind-merge:
+        specifier: ^3.3.1
+        version: 3.3.1
       true-myth:
         specifier: ^9.2.0
         version: 9.2.0
@@ -357,6 +366,12 @@ packages:
   '@floating-ui/utils@0.2.10':
     resolution: {integrity: sha512-aGTxbpbg8/b5JfU1HXSrbH3wXZuLPJcNEcZQFMxLs3oSzgtVu6nFPkbbGGUvBcUjKV2YyB9Wxxabo+HEH9tcRQ==}
 
+  '@fontsource-variable/inter@5.2.8':
+    resolution: {integrity: sha512-kOfP2D+ykbcX/P3IFnokOhVRNoTozo5/JxhAIVYLpea/UBmCQ/YWPBfWIDuBImXX/15KH+eKh4xpEUyS2sQQGQ==}
+
+  '@fontsource/ibm-plex-mono@5.2.7':
+    resolution: {integrity: sha512-MKAb8qV+CaiMQn2B0dIi1OV3565NYzp3WN5b4oT6LTkk+F0jR6j0ZN+5BKJiIhffDC3rtBULsYZE65+0018z9w==}
+
   '@headlessui/react@2.2.9':
     resolution: {integrity: sha512-Mb+Un58gwBn0/yWZfyrCh0TJyurtT+dETj7YHleylHk5od3dv2XqETPGWMyQ5/7sYN7oWdyM1u9MvC0OC8UmzQ==}
     engines: {node: '>=10'}
@@ -2508,6 +2523,9 @@ packages:
     resolution: {integrity: sha512-yEFYrVhod+hdNyx7g5Bnkkb0G6si8HJurOoOEgC8B/O0uXLHlaey/65KRv6cuWBNhBgHKAROVpc7QyYqE5gFng==}
     engines: {node: '>=20'}
 
+  tailwind-merge@3.3.1:
+    resolution: {integrity: sha512-gBXpgUm/3rp1lMZZrM/w7D8GKqshif0zAymAhbCyIt8KMe+0v9DQ7cdYLR4FHH/cKpdTXb+A/tKKU3eolfsI+g==}
+
   tailwindcss@4.1.15:
     resolution: {integrity: sha512-k2WLnWkYFkdpRv+Oby3EBXIyQC8/s1HOFMBUViwtAh6Z5uAozeUSMQlIsn/c6Q2iJzqG6aJT3wdPaRNj70iYxQ==}
 
@@ -2912,6 +2930,10 @@ snapshots:
 
   '@floating-ui/utils@0.2.10': {}
 
+  '@fontsource-variable/inter@5.2.8': {}
+
+  '@fontsource/ibm-plex-mono@5.2.7': {}
+
   '@headlessui/react@2.2.9(react-dom@19.2.0(react@19.2.0))(react@19.2.0)':
     dependencies:
       '@floating-ui/react': 0.26.28(react-dom@19.2.0(react@19.2.0))(react@19.2.0)
@@ -5139,6 +5161,8 @@ snapshots:
 
   tagged-tag@1.0.0: {}
 
+  tailwind-merge@3.3.1: {}
+
   tailwindcss@4.1.15: {}
 
   tapable@2.3.0: {}