feat: more granular local environment checks (#870)

* feat: more granular local environment checks

* refactor: improve PR #870 with i18n, shadcn Select, and testable helpers

- Extract is_valid_shell, is_valid_shell_flag, default_flag_for_shell
  to module-level #[cfg(windows)] functions for testability
- Add unit tests for extracted helper functions
- Replace native <select> with shadcn/ui Select components
- Extract env badge ternary to ENV_BADGE_CONFIG Record lookup
- Add i18n keys for env badges and WSL selectors (zh/en/ja)
- Unify initial useEffect load path with loadAllToolVersions()

* fix: prevent useEffect re-firing on wslShellByTool changes

The useEffect that loads initial tool versions depended on
loadAllToolVersions, which in turn depended on wslShellByTool.
This caused a full re-fetch of all 4 tools every time the user
changed a WSL shell or flag, racing with the single-tool refresh.

Fix: use empty deps [] since this is a mount-only effect. The
refresh button and shell/flag handlers cover subsequent updates.

---------

Co-authored-by: Jason <farion1231@gmail.com>

src/lib/api/settings.ts

@@ -169,15 +169,23 @@ export const settingsApi = {
     return await invoke("get_auto_launch_status");
   },
 
-  async getToolVersions(): Promise<
+  async getToolVersions(
+    tools?: string[],
+    wslShellByTool?: Record<
+      string,
+      { wslShell?: string | null; wslShellFlag?: string | null }
+    >,
+  ): Promise<
     Array<{
       name: string;
       version: string | null;
       latest_version: string | null;
       error: string | null;
+      env_type: "windows" | "wsl" | "macos" | "linux" | "unknown";
+      wsl_distro: string | null;
     }>
   > {
-    return await invoke("get_tool_versions");
+    return await invoke("get_tool_versions", { tools, wslShellByTool });
   },
 
   async getRectifierConfig(): Promise<RectifierConfig> {