feat(settings): unified server-URL resolver + field; adopt in Jellyseerr

Type a loose address (media.example.com, https://…, host:port) and the app finds the working, canonical URL.

- utils/serverUrl: generic candidate generator (https-first, port/path preserved, no Jellyfin-specific ports), parallel-probe resolver, numeric semver compare, and a Jellyseerr probe (/api/v1/status, min 2.0.0).

- useServerUrlResolver: idle -> resolving -> ok | error state machine with cancellation.

- ServerUrlField: shared input that auto-resolves on blur, inline status chip (tap to re-test) + resolved URL, persists the canonical URL.

- Jellyseerr settings adopt the field and log in with the resolved URL. Probe contract makes Streamystats/Jellyfin/Merlin a drop-in follow-up.

utils/serverUrl/index.ts

@@ -0,0 +1,14 @@
+export {
+  getServerUrlCandidates,
+  type ParsedServerInput,
+  parseServerInput,
+} from "./candidates";
+export { jellyseerrProbe } from "./probes/jellyseerr";
+export {
+  type ResolveFailureReason,
+  type ResolveOptions,
+  type ResolveResult,
+  resolveServerUrl,
+} from "./resolve";
+export { isVersionBelow } from "./semver";
+export type { ServerProbe, ServerProbeOutcome } from "./types";