feat(mobile): continue read-only sessions

apps/mobile/src/app/(app)/agent-chat/new.tsx

@@ -11,6 +11,7 @@ import {
   useNewSessionModelState,
 } from '@/components/agents/new-session-model-provider';
 import { pickAgentAttachments } from '@/components/agents/attachment-picker';
+import { useNewSessionPrefillTargets } from '@/components/agents/use-new-session-prefill';
 import { ScreenHeader } from '@/components/screen-header';
 import { AGENT_ATTACHMENT_MAX_FILES } from '@/lib/agent-attachments/constants';
 import { useAgentAttachmentUpload } from '@/lib/agent-attachments/use-agent-attachment-upload';
@@ -44,7 +45,6 @@ function NewSessionScreenBody() {
   }>();
   const shareId: string | undefined = Array.isArray(shareIdParam) ? shareIdParam[0] : shareIdParam;
 
-  const [selectedRepo, setSelectedRepo] = useState('');
   const [runOnInstance, setRunOnInstance] = useState<InstancePickerInstance | null>(null);
   const [isCreating, setIsCreating] = useState(false);
   const [isSubmitting, setIsSubmitting] = useState(false);
@@ -73,6 +73,13 @@ function NewSessionScreenBody() {
     refreshReposForceFresh,
   } = useNewSessionRepos({ organizationId });
 
+  const { selectedRepo, setSelectedRepo } = useNewSessionPrefillTargets({
+    repositories,
+    reposSettled: view === 'repos' && repositories.length > 0,
+    models,
+    modelsSettled: !isLoadingModels && !isModelsError && models.length > 0,
+  });
+
   // Keep the inline selector and picker list in sync.
   const {
     data: instancesData,

apps/mobile/src/components/agents/new-session-model-provider.tsx

@@ -10,6 +10,8 @@ import {
 } from 'react';
 
 import { type AgentMode } from '@/components/agents/mode-selector';
+import { resolvePrefillModel } from '@/components/agents/new-session-prefill';
+import { useNewSessionPrefill } from '@/components/agents/use-new-session-prefill';
 import { RemoteSpawnInheritanceProvider } from '@/components/agents/use-remote-spawn-dispatch';
 import { useAvailableModels } from '@/lib/hooks/use-available-models';
 import { useAutoSelectModel } from '@/lib/hooks/use-auto-select-model';
@@ -42,16 +44,18 @@ export function NewSessionModelProvider({
   organizationId,
   children,
 }: Readonly<NewSessionModelProviderProps>) {
-  const [mode, setMode] = useState<AgentMode>('code');
+  const prefill = useNewSessionPrefill();
+  const [mode, setMode] = useState<AgentMode>(prefill.mode);
   const [model, setModel] = useState('');
   const [variant, setVariant] = useState('');
   const { models } = useAvailableModels(organizationId);
   const autoSelected = useAutoSelectModel(models, organizationId);
   const hasAppliedAutoSelection = useRef(false);
-  if (!hasAppliedAutoSelection.current && autoSelected.model && !model) {
+  const initialSelection = resolvePrefillModel(models, prefill) ?? autoSelected;
+  if (!hasAppliedAutoSelection.current && initialSelection.model && !model) {
     hasAppliedAutoSelection.current = true;
-    setModel(autoSelected.model);
-    setVariant(autoSelected.variant);
+    setModel(initialSelection.model);
+    setVariant(initialSelection.variant);
   }
   const state = useMemo(
     () => ({ mode, setMode, model, setModel, variant, setVariant }),