fix: replace vue3-flag-icons with custom CSS-only flag icons

- Remove vue3-flag-icons dependency (was causing slow loading)
- Create custom flag-icons.css with only cn and us flags (inline SVG)
- Update language-change.vue to use CSS-based flag icons
- Delete vue3-flag-icons type declaration file
- Flag icons now load instantly without any JavaScript overhead

frontend/pnpm-lock.yaml

@@ -110,9 +110,6 @@ importers:
       vue-sonner:
         specifier: ^2.0.9
         version: 2.0.9
-      vue3-flag-icons:
-        specifier: ^0.1.4
-        version: 0.1.4(vue@3.5.32(typescript@5.9.3))
       zod:
         specifier: ^4.3.6
         version: 4.3.6
@@ -2170,9 +2167,6 @@ packages:
     resolution: {integrity: sha512-78/PXT1wlLLDgTzDs7sjq9hzz0vXD+zn+7wypEe4fXQxCmdmqfGsEPQxmiCSQI3ajFV91bVSsvNtrJRiW6nGng==}
     engines: {node: '>=10'}
 
-  flag-icons@7.5.0:
-    resolution: {integrity: sha512-kd+MNXviFIg5hijH766tt+3x76ele1AXlo4zDdCxIvqWZhKt4T83bOtxUOOMlTx/EcFdUMH5yvQgYlFh1EqqFg==}
-
   flat-cache@4.0.1:
     resolution: {integrity: sha512-f7ccFPK3SXFHpx15UIGyRJ/FJQctuKZ0zVuN3frBo4HnK3cay9VEW0R6yPYFHC0AgqhukPzKjq22t5DmAyqGyw==}
     engines: {node: '>=16'}
@@ -3404,11 +3398,6 @@ packages:
     peerDependencies:
       typescript: '>=5.0.0'
 
-  vue3-flag-icons@0.1.4:
-    resolution: {integrity: sha512-bJrrZuVHcs5XCW1CiXG3gpZnkzczk3gXlLgVmKt4XTeKRb3U/qt57hNtTP2ybXEXaigE26WxhO9rVXF9gsL7Dg==}
-    peerDependencies:
-      vue: ^3.5.0
-
   vue@3.5.32:
     resolution: {integrity: sha512-vM4z4Q9tTafVfMAK7IVzmxg34rSzTFMyIe0UUEijUCkn9+23lj0WRfA83dg7eQZIUlgOSGrkViIaCfqSAUXsMw==}
     peerDependencies:
@@ -5442,8 +5431,6 @@ snapshots:
       locate-path: 6.0.0
       path-exists: 4.0.0
 
-  flag-icons@7.5.0: {}
-
   flat-cache@4.0.1:
     dependencies:
       flatted: 3.4.2
@@ -6793,11 +6780,6 @@ snapshots:
       '@vue/language-core': 3.2.6
       typescript: 5.9.3
 
-  vue3-flag-icons@0.1.4(vue@3.5.32(typescript@5.9.3)):
-    dependencies:
-      flag-icons: 7.5.0
-      vue: 3.5.32(typescript@5.9.3)
-
   vue@3.5.32(typescript@5.9.3):
     dependencies:
       '@vue/compiler-dom': 3.5.32