feat(firmware): list all announced versions with usable/unavailable status, support rollback

Firmware update modal now shows every version from Bambu's wiki release
  history, each badged Usable/Unavailable/Installed. Selecting a usable row
  — newer or older than current — swaps the release notes and enables
  install for that version, so rollback no longer requires hand-flashing.

  Wiki scraper tightened to only read heading-anchor ids (h-XXXXXXXX-YYYYMMDD)
  instead of any XX.XX.XX.XX substring, eliminating false positives like an
  AMS firmware version mentioned in an H2D changelog being listed as H2D
  firmware.

  Refs #568

frontend/src/utils/firmwareVersion.ts

@@ -0,0 +1,16 @@
+/**
+ * Compare two Bambu Lab firmware version strings (format: "XX.XX.XX.XX").
+ *
+ * Returns a negative number if `a` < `b`, zero if equal, positive if `a` > `b`.
+ * Missing trailing segments are treated as 0.
+ */
+export function compareFwVersions(a: string, b: string): number {
+  const pa = a.split('.').map((n) => parseInt(n, 10) || 0);
+  const pb = b.split('.').map((n) => parseInt(n, 10) || 0);
+  while (pa.length < 4) pa.push(0);
+  while (pb.length < 4) pb.push(0);
+  for (let i = 0; i < 4; i++) {
+    if (pa[i] !== pb[i]) return pa[i] - pb[i];
+  }
+  return 0;
+}