fix: enforce rollout gates across backend entry points

src/convex/functions.ts

@@ -5,6 +5,7 @@ import {
 } from "convex/server";
 import { v } from "convex/values";
 import { assetValidator } from "./schema";
+import { capabilityEnabled, parseCapabilityAllowlist } from "../lib/server/release-gate";
 
 const MAX_ASSET_CHUNK = 250;
 const SYNC_LEASE_MS = 5 * 60 * 1000;
@@ -39,6 +40,16 @@ function assertBridge(secret: string): void {
   }
 }
 
+function assertDeploymentCapability(capability: 'asset_sync'): void {
+  let enabled = false;
+  try {
+    enabled = capabilityEnabled(capability, parseCapabilityAllowlist(process.env.APP_CAPABILITY_ALLOWLIST));
+  } catch {
+    // Invalid backend rollout configuration fails closed.
+  }
+  if (!enabled) throw new Error(`The ${capability} capability is disabled by deployment configuration.`);
+}
+
 function constantTimeEqual(a: string, b: string): boolean {
   let difference = a.length ^ b.length;
   const length = Math.max(a.length, b.length);
@@ -412,6 +423,7 @@ export const bridgeBeginSync = mutationGeneric({
   args: { ...bridgeArgs, ...characterArgs },
   handler: async (ctx, args) => {
     assertBridge(args.bridgeSecret);
+    assertDeploymentCapability('asset_sync');
     const character = await findCharacter(ctx, args.userId, args.characterId);
     if (!character) throw new Error("Character not found");
     const timestamp = now();
@@ -446,6 +458,7 @@ export const bridgeStageAssets = mutationGeneric({
   },
   handler: async (ctx, args) => {
     assertBridge(args.bridgeSecret);
+    assertDeploymentCapability('asset_sync');
     if (!Number.isInteger(args.index) || args.index < 0 || args.assets.length > MAX_ASSET_CHUNK) {
       throw new Error("Invalid asset chunk");
     }
@@ -511,6 +524,7 @@ export const bridgeFinishSync = mutationGeneric({
   },
   handler: async (ctx, args) => {
     assertBridge(args.bridgeSecret);
+    assertDeploymentCapability('asset_sync');
     const timestamp = now();
     if (
       !Number.isFinite(args.syncedAt) ||
@@ -574,6 +588,7 @@ export const bridgeFailSync = mutationGeneric({
   args: { ...bridgeArgs, ...characterArgs, generation: v.string(), error: v.string() },
   handler: async (ctx, args) => {
     assertBridge(args.bridgeSecret);
+    assertDeploymentCapability('asset_sync');
     const character = await findCharacter(ctx, args.userId, args.characterId);
     if (!character || character.syncGeneration !== args.generation) {
       throw new Error("Synchronization generation is not current");