[mod] client/simple: client plugins (#5406)

* [mod] client/simple: client plugins

Defines a new interface for client side *"plugins"* that coexist with server
side plugin system. Each plugin (e.g., `InfiniteScroll`) extends the base
`ts Plugin`. Client side plugins are independent and lazy‑loaded via `router.ts`
when their `load()` conditions are met. On each navigation request, all
applicable plugins are instanced.

Since these are client side plugins, we can only invoke them once DOM is fully
loaded. E.g. `Calculator` will not render a new `answer` block until fully
loaded and executed.

For some plugins, we might want to handle its availability in `settings.yml`
and toggle in UI, like we do for server side plugins. In that case, we extend
`py Plugin` instancing only the information and then checking client side if
[`settings.plugins`](https://github.com/inetol/searxng/blob/1ad832b1dc33f3f388da361ff2459b05dc86a164/client/simple/src/js/toolkit.ts#L134)
array has the plugin id.

* [mod] client/simple: rebuild static

client/simple/vite.config.ts

@@ -46,39 +46,34 @@ export default {
     sourcemap: true,
     rolldownOptions: {
       input: {
-        // build CSS files
-        "searxng-ltr.css": `${PATH.src}/less/style-ltr.less`,
-        "searxng-rtl.css": `${PATH.src}/less/style-rtl.less`,
-        "rss.css": `${PATH.src}/less/rss.less`,
+        // entrypoint
+        core: `${PATH.src}/js/index.ts`,
 
-        // build script files
-        "searxng.core": `${PATH.src}/js/core/index.ts`,
-
-        // ol pkg
-        ol: `${PATH.src}/js/pkg/ol.ts`,
-        "ol.css": `${PATH.modules}/ol/ol.css`
+        // stylesheets
+        ltr: `${PATH.src}/less/style-ltr.less`,
+        rtl: `${PATH.src}/less/style-rtl.less`,
+        rss: `${PATH.src}/less/rss.less`
       },
 
       // file naming conventions / pathnames are relative to outDir (PATH.dist)
       output: {
-        entryFileNames: "js/[name].min.js",
-        chunkFileNames: "js/[name].min.js",
+        entryFileNames: "sxng-[name].min.js",
+        chunkFileNames: "chunk/[hash].min.js",
         assetFileNames: ({ names }: PreRenderedAsset): string => {
           const [name] = names;
 
-          const extension = name?.split(".").pop();
-          switch (extension) {
+          switch (name?.split(".").pop()) {
             case "css":
-              return "css/[name].min[extname]";
-            case "js":
-              return "js/[name].min[extname]";
-            case "png":
-            case "svg":
-              return "img/[name][extname]";
+              return "sxng-[name].min[extname]";
             default:
-              console.warn("Unknown asset:", name);
-              return "[name][extname]";
+              return "sxng-[name][extname]";
           }
+        },
+        sanitizeFileName: (name: string): string => {
+          return name
+            .normalize("NFD")
+            .replace(/[^a-zA-Z0-9.-]/g, "_")
+            .toLowerCase();
         }
       }
     }