feat(FN-1754): raise global max concurrent ceiling to 10000

- Enforce 10000 upper bound in CentralCore for globalMaxConcurrent setting
- Add 10000 upper bound validation in the project settings API route
- Raise max ceiling in SettingsModal from previous limit to 10000
- Add route test verifying the 10000 upper bound is enforced

packages/core/src/central-core.ts

@@ -1748,6 +1748,13 @@ export class CentralCore extends EventEmitter<CentralCoreEvents> {
   ): Promise<GlobalConcurrencyState> {
     this.ensureInitialized();
 
+    if (
+      updates.globalMaxConcurrent !== undefined &&
+      (!Number.isFinite(updates.globalMaxConcurrent) || updates.globalMaxConcurrent < 1 || updates.globalMaxConcurrent > 10000)
+    ) {
+      throw new Error("globalMaxConcurrent must be between 1 and 10000");
+    }
+
     const current = await this.getGlobalConcurrencyState();
     const updated = {
       ...current,