feat(backend): queue-time runtime/profile validation; job.runtime authoritative in worker

packages/backend/convex/aiProviderProfiles.ts

@@ -4,6 +4,7 @@ import type { Doc, Id } from './_generated/dataModel';
 import type { MutationCtx } from './_generated/server';
 import { internalMutation, mutation, query } from './_generated/server';
 import { getRequiredUserId, optionalText } from './model';
+import { runtimesForProfile } from './runtimeSupport';
 
 type AiProviderProfileWithDefault = Doc<'aiProviderProfiles'> & {
   isDefault?: boolean;
@@ -59,6 +60,7 @@ const publicProfile = (
   reasoningEffort: profile.reasoningEffort,
   enabled: profile.enabled,
   configured: isConfigured(profile),
+  supportedRuntimes: runtimesForProfile(profile),
   isDefault: profile._id === defaultProfileId,
   createdAt: profile.createdAt,
   updatedAt: profile.updatedAt,