feat: add adapter picker for imported agents

When importing a company, users can now choose the adapter type for each
imported agent. Defaults to the current company CEO's adapter type (or
claude_local if none). Includes an expandable "configure adapter" section
per agent that renders the adapter-specific config fields.

- Added adapterOverrides to import request schema and types
- Built AdapterPickerList UI component in CompanyImport.tsx
- Backend applies adapter overrides when creating/updating agents

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/shared/src/index.ts

@@ -185,6 +185,7 @@ export type {
   CompanyPortabilityPreviewProjectPlan,
   CompanyPortabilityPreviewIssuePlan,
   CompanyPortabilityPreviewResult,
+  CompanyPortabilityAdapterOverride,
   CompanyPortabilityImportRequest,
   CompanyPortabilityImportResult,
   CompanyPortabilityExportRequest,