docs(docs): fix cursor handling and hover tip refactor in docs UI components

apps/docs/islands/SolvedRing.tsx

@@ -57,14 +57,14 @@ export default function SolvedRing() {
   const done = rows.reduce((n, r) => n + r.done, 0);
   const span = SWEEP - GAP * (rows.length - 1);
 
+  const segments: ((typeof rows)[number] & { from: number; to: number; solvedTo: number })[] = [];
   let cursor = START;
-  const segments = rows.map((r) => {
+  for (const r of rows) {
     const size = total > 0 ? (span * r.total) / total : 0;
-    const from = cursor;
-    cursor -= size + GAP;
     const solved = r.total > 0 ? size * (r.done / r.total) : 0;
-    return { ...r, from, to: from - size, solvedTo: from - solved };
-  });
+    segments.push({ ...r, from: cursor, to: cursor - size, solvedTo: cursor - solved });
+    cursor -= size + GAP;
+  }
 
   const focused = focus ? rows.find((r) => r.difficulty === focus) : undefined;
   const arc = { innerRadius: "80%", outerRadius: "88%", cornerRadius: 99, stroke: "none", dataKey: "value" } as const;