refactor: create modular hooks and integrate API key input

- Create custom hooks for state management:
  - useProviderCategory: manages provider category state
  - useApiKeyState: manages API key input with auto-sync to config
  - useBaseUrlState: manages base URL for Claude and Codex
  - useModelState: manages model selection state

- Integrate API key input into simplified ProviderForm:
  - Add ApiKeyInput component for Claude mode
  - Auto-populate API key into settings config
  - Disable for official providers

- Fix EndpointSpeedTest type errors:
  - Fix import paths to use @ alias
  - Add temporary type definitions
  - Format all TODO comments properly
  - Remove incorrect type assertions
  - Comment out unimplemented window.api checks

All TypeScript type checks now pass.

src/components/providers/forms/hooks/index.ts

@@ -0,0 +1,4 @@
+export { useProviderCategory } from "./useProviderCategory";
+export { useApiKeyState } from "./useApiKeyState";
+export { useBaseUrlState } from "./useBaseUrlState";
+export { useModelState } from "./useModelState";