Add NFC normalization to all FormData inputs across 41 server actions

All user-supplied string values from FormData now go through
String.prototype.normalize('NFC') to prevent Unicode homoglyph
attacks and canonicalization bypasses. NFC is idempotent for
already-normalized strings, so this is a pure security improvement
with zero behavioral change for legitimate users.

src/actions/admin-maintenance.ts

@@ -39,11 +39,11 @@ export async function saveMaintenance(formData: FormData): Promise<void> {
   // emulator/Laravel side expects.
   const enabled = formData.get("enabled") != null ? "1" : "0";
 
-  const message = String(formData.get("message") ?? "");
+  const message = String(formData.get("message") ?? "").normalize("NFC");
 
   // Coerce the rank to a non-negative integer; fall back to AtomCMS's default
   // of 5 when the field is blank or garbage.
-  const rawRank = String(formData.get("min_rank") ?? "").trim();
+  const rawRank = String(formData.get("min_rank") ?? "").normalize("NFC").trim();
   const parsedRank = Number.parseInt(rawRank, 10);
   const minRank = Number.isFinite(parsedRank) && parsedRank >= 0 ? parsedRank : 5;