Improve mobile selectors and sheet inputs

Keep sheet text inputs native-owned to avoid React Native controlled input flicker during fast typing. Add reset keys for fields that need programmatic clears, and move model, mode, and thinking pickers onto shared combobox rows with fuzzy ranked search and native virtualization.

packages/app/src/screens/workspace/workspace-import-sheet.tsx

@@ -5,7 +5,7 @@ import type { DaemonClient, FetchRecentProviderSessionEntry } from "@server/clie
 import type { AgentProvider } from "@server/server/agent/agent-sdk-types";
 import { IMPORTABLE_PROVIDERS } from "@server/shared/importable-providers";
 import { StyleSheet, useUnistyles } from "react-native-unistyles";
-import { AdaptiveModalSheet } from "@/components/adaptive-modal-sheet";
+import { AdaptiveModalSheet, type SheetHeader } from "@/components/adaptive-modal-sheet";
 import { LoadingSpinner } from "@/components/ui/loading-spinner";
 import { SegmentedControl, type SegmentedControlOption } from "@/components/ui/segmented-control";
 import { getProviderIcon } from "@/components/provider-icons";
@@ -13,6 +13,7 @@ import { formatTimeAgo } from "@/utils/time";
 import { useProvidersSnapshot } from "@/hooks/use-providers-snapshot";
 
 const IMPORTABLE_PROVIDER_IDS: Set<string> = new Set(IMPORTABLE_PROVIDERS);
+const IMPORT_SESSION_HEADER: SheetHeader = { title: "Import session" };
 const PER_PROVIDER_LIMIT = 15;
 const IMPORT_SHEET_SNAP_POINTS = ["70%", "92%"];
 const DISABLED_ACCESSIBILITY_STATE = { disabled: true };
@@ -435,7 +436,7 @@ export function WorkspaceImportSheet({
     <AdaptiveModalSheet
       visible={visible}
       onClose={onClose}
-      title="Import session"
+      header={IMPORT_SESSION_HEADER}
       testID="workspace-import-sheet"
       desktopMaxWidth={560}
       snapPoints={IMPORT_SHEET_SNAP_POINTS}