fix(shared): profile.ts must not reference the URL global type

packages/shared compiles without the DOM or Node type libraries, so `URL` has
no type there even though it exists at runtime everywhere this code runs. The
web and server builds resolved the same file under their own libs and passed;
only the shared package's own `tsc` — which CI runs first — failed, on both
runners. Reach the constructor through globalThis with a minimal structural
type instead of pulling a lib into a types-only package. Runtime unchanged,
so the deployed site (82798d5c) needs no redeploy for this.

Lesson recorded for the local checklist: run `pnpm --filter @backspace/shared
build` too — the root `typecheck` script already does; the web build alone
does not.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

packages/shared/src/profile.ts

@@ -136,6 +136,18 @@ const HEX = /^#[0-9a-fA-F]{6}$/;
  *  proxied — a profile is not a place to load arbitrary third-party pixels. */
 const COVER_HOSTS = ['cdn.cloudflare.steamstatic.com', 'cdn.akamai.steamstatic.com', 'shared.cloudflare.steamstatic.com', 'shared.akamai.steamstatic.com', 'steamcdn-a.akamaihd.net'];
 
+/**
+ * This package compiles without the DOM or Node type libraries, so the `URL`
+ * global has no type here even though it exists at runtime everywhere this
+ * code runs (browsers, Node ≥ 10). Reach it through globalThis with a minimal
+ * structural type rather than pulling a whole lib into a types-only package.
+ */
+interface UrlLike { protocol: string; hostname: string; toString(): string }
+const UrlCtor = (globalThis as unknown as { URL: new (s: string) => UrlLike }).URL;
+function parseUrl(value: string): UrlLike | null {
+  try { return new UrlCtor(value); } catch { return null; }
+}
+
 function pick<T extends string>(value: unknown, allowed: readonly T[], fallback: T): T {
   return typeof value === 'string' && (allowed as readonly string[]).includes(value) ? (value as T) : fallback;
 }
@@ -149,15 +161,14 @@ function httpsUrl(value: unknown, max: number): string | null {
   if (typeof value !== 'string') return null;
   const v = value.trim();
   if (v.length === 0 || v.length > max) return null;
-  try {
-    const u = new URL(v);
-    return u.protocol === 'https:' ? u.toString() : null;
-  } catch { return null; }
+  const u = parseUrl(v);
+  return u && u.protocol === 'https:' ? u.toString() : null;
 }
 function coverUrl(value: unknown): string | null {
   const u = httpsUrl(value, 300);
   if (!u) return null;
-  try { return COVER_HOSTS.includes(new URL(u).hostname) ? u : null; } catch { return null; }
+  const parsed = parseUrl(u);
+  return parsed && COVER_HOSTS.includes(parsed.hostname) ? u : null;
 }
 /** First grapheme only — one emoji, not a sentence hidden in the tag. */
 function oneGrapheme(value: unknown): string {
@@ -209,7 +220,7 @@ export function normalizeProfileStyle(input: unknown): ProfileStyle {
         const o = (l && typeof l === 'object' ? l : {}) as Record<string, unknown>;
         const url = httpsUrl(o.url, PROFILE_LIMITS.linkUrl);
         if (!url) return null;
-        const label = str(o.label, PROFILE_LIMITS.linkLabel) || new URL(url).hostname.replace(/^www\./, '');
+        const label = str(o.label, PROFILE_LIMITS.linkLabel) || (parseUrl(url)?.hostname ?? url).replace(/^www\./, '');
         return { label, url };
       }).filter((l): l is ProfileLink => l !== null).slice(0, PROFILE_LIMITS.links)
     : [];