Add Cursor support to setup import (#33426)

## What changed

- Detect and import supported Cursor settings, sandbox permissions, MCP servers,
  project instructions, hooks, agents, commands, plugins, and recent chat
  sessions.
- Update the `/import` flow to check Claude Code and Cursor, prompting for a
  source when both have importable data.
- Add `migrationSource` to the app-server detect and import requests so each
  operation uses the selected adapter, while retaining `source` for import
  attribution and backwards compatibility.

## Testing

- Add coverage for Cursor config conversion, hooks, plugins, session discovery
  and conversion, app-server imports, and TUI source selection.

GitOrigin-RevId: a65a1511b6c1c2f9e3e0cfe4f816bb435807282e

codex-rs/tui/src/external_agent_config_migration_model.rs

@@ -79,8 +79,8 @@ pub(crate) fn external_agent_config_migration_item_label(
     item: &ExternalAgentConfigMigrationItem,
 ) -> &'static str {
     match item.item_type {
-        ExternalAgentConfigMigrationItemType::AgentsMd => "Instructions (CLAUDE.md -> AGENTS.md)",
-        ExternalAgentConfigMigrationItemType::Config => "Settings (settings.json -> config.toml)",
+        ExternalAgentConfigMigrationItemType::AgentsMd => "Instructions",
+        ExternalAgentConfigMigrationItemType::Config => "Settings",
         ExternalAgentConfigMigrationItemType::Skills => "Skills",
         ExternalAgentConfigMigrationItemType::Plugins => "Plugins",
         ExternalAgentConfigMigrationItemType::McpServerConfig => "MCP servers",