feat: support multi-run for non-Git projects

Creates non-Git multi-runs in the same project directory
Shows concise footer info when worktree isolation is unavailable
Displays default model variants with a friendly label

packages/ui/src/components/multirun/BranchSelector.tsx

@@ -9,7 +9,7 @@ import {
   SelectTrigger,
   SelectValue,
 } from '@/components/ui/select';
-import { useGitStore, useGitBranches, useGitLoadingBranches } from '@/stores/useGitStore';
+import { useGitStore, useGitBranches, useGitLoadingBranches, useGitLoadingStatus, useIsGitRepo } from '@/stores/useGitStore';
 import { useRuntimeAPIs } from '@/hooks/useRuntimeAPIs';
 import { getRootBranch } from '@/lib/worktrees/worktreeStatus';
 import { useI18n } from '@/lib/i18n';
@@ -53,15 +53,26 @@ export interface BranchSelectorState {
 export function useBranchOptions(directory: string | null): BranchSelectorState {
   const { git } = useRuntimeAPIs();
   const branches = useGitBranches(directory);
-  const isLoading = useGitLoadingBranches(directory);
+  const isGitRepo = useIsGitRepo(directory);
+  const isLoadingStatus = useGitLoadingStatus(directory);
+  const isLoadingBranches = useGitLoadingBranches(directory);
   const fetchBranches = useGitStore((state) => state.fetchBranches);
+  const fetchStatus = useGitStore((state) => state.fetchStatus);
+
+  React.useEffect(() => {
+    if (!directory || !git || isGitRepo !== null || isLoadingStatus) return;
+    void fetchStatus(directory, git, { silent: true });
+  }, [directory, git, fetchStatus, isGitRepo, isLoadingStatus]);
 
   // Fetch branches if not cached
   React.useEffect(() => {
     if (!directory || !git) return;
+    if (isGitRepo !== true) return;
     if (branches?.all) return; // Already cached
     void fetchBranches(directory, git);
-  }, [directory, git, branches?.all, fetchBranches]);
+  }, [directory, git, isGitRepo, branches?.all, fetchBranches]);
+
+  const isLoading = isLoadingStatus || (isGitRepo === true && isLoadingBranches);
 
   // Compute local and remote branch lists (same as NewWorktreeDialog)
   const localBranches = React.useMemo(() => {
@@ -82,10 +93,10 @@ export function useBranchOptions(directory: string | null): BranchSelectorState
   // isGitRepository: true if we got branches, false if fetch returned empty, null if not yet loaded
   const isGitRepository = React.useMemo<boolean | null>(() => {
     if (!directory) return null;
+    if (isGitRepo !== null) return isGitRepo;
     if (isLoading) return null;
-    if (!branches) return null;
-    return Boolean(branches.all);
-  }, [directory, isLoading, branches]);
+    return branches?.all ? true : null;
+  }, [directory, isLoading, branches, isGitRepo]);
 
   return { localBranches, remoteBranches, isLoading, isGitRepository };
 }

packages/ui/src/components/multirun/ModelMultiSelect.tsx

@@ -560,7 +560,11 @@ export const ModelMultiSelect: React.FC<ModelMultiSelectProps> = ({
                             variantValue === DEFAULT_VARIANT_VALUE ? 'text-muted-foreground' : 'text-[color:var(--status-info)]'
                           )}
                         />
-                        <SelectValue placeholder={t('multirun.modelMultiSelect.variant.placeholder')} />
+                        <SelectValue placeholder={t('multirun.modelMultiSelect.variant.placeholder')}>
+                          {(value) => value === DEFAULT_VARIANT_VALUE
+                            ? t('multirun.modelMultiSelect.variant.default')
+                            : value}
+                        </SelectValue>
                       </SelectTrigger>
                       <SelectContent fitContent>
                         <SelectItem value={DEFAULT_VARIANT_VALUE} className="pr-2 [&>span:first-child]:hidden">

packages/ui/src/components/multirun/MultiRunLauncher.tsx

@@ -587,7 +587,12 @@ export const MultiRunLauncher: React.FC<MultiRunLauncherProps> = ({
   };
 
   const isValid = Boolean(
-    name.trim() && prompt.trim() && selectedModels.length >= 2 && worktreeBaseBranch && isGitRepository && !isLoadingWorktreeBaseBranches
+    name.trim() &&
+    prompt.trim() &&
+    selectedModels.length >= 2 &&
+    selectedProjectDirectory &&
+    !isLoadingWorktreeBaseBranches &&
+    (isGitRepository === false || (isGitRepository === true && worktreeBaseBranch))
   );
 
   const configuredSetupCount = setupCommands.filter(cmd => cmd.trim()).length;
@@ -929,6 +934,12 @@ export const MultiRunLauncher: React.FC<MultiRunLauncherProps> = ({
       {/* ── Fixed footer ── */}
       <div className="shrink-0 px-4 sm:px-6 py-3">
         <div className="mx-auto w-full max-w-2xl flex items-center justify-end gap-2">
+          {isGitRepository === false ? (
+            <div className="mr-auto flex min-w-0 items-center gap-1.5 typography-micro text-muted-foreground">
+              <Icon name="information" className="h-3.5 w-3.5 shrink-0" />
+              <span className="truncate">{t('multirun.launcher.project.gitRequired')}</span>
+            </div>
+          ) : null}
           <Button
             type="button"
             variant="ghost"