fix(frontend): star rating hover via StarInput, retire overlay slider

The vendored overlay-slider Stars.svelte never responded under
Svelte 5 - a runes port plus an explicit value/oninput rewrite both
left it inert, which convicted the mechanism rather than its
syntax. Replace it with StarInput.svelte: per-star hover zones with
fractional math (preserves the full 0-10 granularity),
snapshot-and-revert on mouseleave, commit on click, arrow-key
nudging, disabled mode. It reuses the Star SVG leaf so output is
pixel-identical, stays dumb (value in/out, no stores) for the
planned inline-grid editing, and Rating.svelte keeps owning the
words/score math locally. Legacy on:change forwarding and the
slider CSS go with the old file.

frontend/src/helperComponents/Rating.svelte

@@ -1,30 +1,9 @@
 <script lang="ts">
-    import StarRatting from "../star-rating/Stars.svelte";
+    import StarInput from "../star-rating/StarInput.svelte";
 
-    export let score
+    let { score = $bindable(0) }: { score: number } = $props();
 
-    let config = {
-        readOnly: false,
-        countStars: 5,
-        range: {
-            min: 0,
-            max: 5,
-            step: 0.5
-        },
-        score: score / 2,
-        showScore: false,
-        name: "rating",
-        scoreFormat: function(){ return `(${this.score.toFixed(0)}/${this.countStars})` },
-        starConfig: {
-            size: 32,
-            fillColor: '#F9ED4F',
-            strokeColor: "#e2c714",
-            unfilledColor: '#FFF',
-            strokeUnfilledColor: '#000'
-        }
-    }
-
-    const ratingInWords = {
+    const ratingInWords: Record<number, string> = {
         0: "Not Reviewed",
         1: "Appalling",
         2: "Horrible",
@@ -37,14 +16,10 @@
         9: "Great",
         10: "Masterpiece",
     }
-
-    const changeRating = (e: any) => {
-        score = e.target.valueAsNumber * 2
-    }
 </script>
 
 <div>
-    <StarRatting bind:config on:change={changeRating}/>
-    <p>Rating:  {config.score * 2}</p>
-    <p>{ratingInWords[config.score * 2]}</p>
+    <StarInput bind:value={score} min={0} max={10} step={1} />
+    <p>Rating:  {score}</p>
+    <p>{ratingInWords[score]}</p>
 </div>