chore(frontend): Svelte 5 / Vite 8 / Tailwind CSS 4 dependency set

Move the toolchain to Svelte 5.57, Vite 8.3, vite-plugin-svelte 7.3,
svelte-check 4.7.6, svelte-spa-router 5.1.1, Tailwind 4.3 (plus the
new @tailwindcss/vite plugin), flowbite-svelte 1.33 and flowbite
4.0.2.

Dropped outright: svelte-preprocess (only ever handled lang="ts",
which the vite plugin does natively), svelte-headless-table (peers
svelte ^4, dead end - the one table gets rewritten dependency-free),
postcss/autoprefixer (v4 handles transforms internally) and the
vanilla flowbite.js script tag (no data-* usage anywhere; the Svelte
components are self-contained).

Deliberately pinned, not upgraded: typescript stays 5.9
(svelte-check peers ^5||^6, and 7.x is the native-port rewrite) and
@wailsio/runtime stays 3.0.0-beta.20 (must match the Go framework and
CLI exactly - it moves in lockstep with them, never alone).

Fresh lockfile, zero npm vulnerabilities (was ten).

frontend/package.json

@@ -11,26 +11,23 @@
     "check": "svelte-check --tsconfig ./tsconfig.json"
   },
   "devDependencies": {
-    "@sveltejs/vite-plugin-svelte": "^2.4.1",
-    "@tsconfig/svelte": "^4.0.1",
-    "autoprefixer": "^10.4.20",
-    "postcss": "^8.4.45",
-    "svelte": "^4.0.0",
-    "svelte-check": "^3.4.3",
-    "svelte-headless-table": "^0.18.3",
-    "svelte-preprocess": "^5.0.3",
-    "svelte-spa-router": "^4.0.1",
-    "tailwind-merge": "^2.5.2",
-    "tailwindcss": "^3.4.10",
-    "tslib": "^2.7.0",
-    "typescript": "^5.0.0",
-    "vite": "^4.5.5"
+    "@sveltejs/vite-plugin-svelte": "^7.3.0",
+    "@tailwindcss/vite": "^4.3.3",
+    "@tsconfig/svelte": "^5.0.8",
+    "svelte": "^5.57.0",
+    "svelte-check": "^4.7.6",
+    "svelte-spa-router": "^5.1.1",
+    "tailwind-merge": "^3.7.0",
+    "tailwindcss": "^4.3.3",
+    "tslib": "^2.8.0",
+    "typescript": "^5.9.3",
+    "vite": "^8.3.0"
   },
   "dependencies": {
     "@popperjs/core": "^2.11.8",
     "@wailsio/runtime": "3.0.0-beta.20",
-    "flowbite": "^2.5.1",
-    "flowbite-svelte": "^0.46.16",
-    "moment": "^2.30.1"
+    "flowbite": "^4.0.2",
+    "flowbite-svelte": "^1.33.1",
+    "moment": "^2.31.0"
   }
 }