chore: remove un(directly)used dependency and cleanup Knip config

vite-plugin-pwa is indeed used but it's a @vite-pwa/nuxt dependency, no need to declare it directly at top level.

I then followed Knip configuration hints to clean it up.

```
Configuration hints (5)
nuxt             docs  …ip.json  Remove from ignoreDependencies
…mple-git-hooks        …ip.json  Remove from ignoreBinaries
lint-staged            …ip.json  Remove from ignoreBinaries
lex                    …ip.json  Remove from ignoreBinaries
tests/**/*.ts          …ip.json  Refine project pattern (no mat…
```

Author: wojtekmaj

knip.json

@@ -2,7 +2,6 @@
   "$schema": "https://unpkg.com/knip@5/schema.json",
   "includeEntryExports": true,
   "ignoreExportsUsedInFile": true,
-  "ignoreBinaries": ["simple-git-hooks", "lint-staged", "lex"],
   "ignore": ["shared/types/lexicons/**"],
   "workspaces": {
     ".": {
@@ -28,7 +27,6 @@
         "server/**/*.ts!",
         "shared/**/*.ts!",
         "test/**/*.ts",
-        "tests/**/*.ts",
         "lunaria/**/*.ts",
         "modules/**/*.ts!",
         "i18n/**/*.ts!"
@@ -54,7 +52,7 @@
     },
     "docs": {
       "entry": ["app/app.config.ts"],
-      "ignoreDependencies": ["docus", "better-sqlite3", "nuxt"]
+      "ignoreDependencies": ["docus", "better-sqlite3"]
     }
   }
 }

package.json

@@ -106,7 +106,6 @@
     "typescript": "5.9.3",
     "unocss": "66.6.0",
     "unplugin-vue-router": "0.19.2",
-    "vite-plugin-pwa": "1.2.0",
     "vite-plus": "0.0.0-833c515fa25cef20905a7f9affb156dfa6f151ab",
     "vitest": "npm:@voidzero-dev/vite-plus-test@0.0.0-833c515fa25cef20905a7f9affb156dfa6f151ab",
     "vitest-environment-nuxt": "1.0.1",