feat(kon): add first-run hardware probe and model recommendation wizard

- New probe_system command: returns RAM, CPU, OS info
- New rank_models command: scores models against detected hardware
- FirstRunPage.svelte: hardware summary, ranked model list with
  "Recommended" badge on top pick, download progress bar, skip option
- First-run detection in layout: checks list_models + list_parakeet_models,
  shows wizard if both empty
- Sidebar hidden during first-run for clean wizard experience
- clippy clean

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src-tauri/src/commands/mod.rs

@@ -1,5 +1,6 @@
 pub mod audio;
 pub mod clipboard;
+pub mod hardware;
 pub mod llm;
 pub mod models;
 pub mod transcription;