fix(sync): honor per-spoon auto-sync settings

packages/backend/convex/syncGating.ts

@@ -0,0 +1,19 @@
+export const shouldAutoSync = (
+  settings: {
+    autoSyncEnabled: boolean;
+    requireCleanCompareForSync: boolean;
+  },
+  ctx: { status: string; forkAheadBy: number },
+): boolean => {
+  if (!settings.autoSyncEnabled) return false;
+  if (ctx.status !== 'behind') return false;
+  if (settings.requireCleanCompareForSync && ctx.forkAheadBy !== 0) {
+    return false;
+  }
+  return ctx.forkAheadBy === 0;
+};
+
+export const shouldCreateReviewThread = (
+  settings: { autoReviewEnabled: boolean },
+  ctx: { status: string },
+): boolean => settings.autoReviewEnabled && ctx.status === 'diverged';