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/hardware.rs

@@ -0,0 +1,69 @@
+use serde::Serialize;
+
+use kon_core::hardware::{self, Os};
+use kon_core::recommendation;
+
+#[derive(Serialize)]
+pub struct SystemInfo {
+    pub ram_mb: u64,
+    pub cpu_brand: String,
+    pub cpu_cores: usize,
+    pub os: String,
+    pub gpu: Option<String>,
+}
+
+#[derive(Serialize)]
+pub struct ModelRecommendation {
+    pub id: String,
+    pub display_name: &'static str,
+    pub disk_size_mb: u64,
+    pub ram_required_mb: u64,
+    pub description: &'static str,
+    pub score: f64,
+    pub reason: String,
+    pub is_downloaded: bool,
+}
+
+/// Probe system hardware and return a summary.
+#[tauri::command]
+pub fn probe_system() -> Result<SystemInfo, String> {
+    let profile = hardware::probe_system();
+    Ok(SystemInfo {
+        ram_mb: profile.ram.0,
+        cpu_brand: profile.cpu.brand,
+        cpu_cores: profile.cpu.core_count,
+        os: match profile.os {
+            Os::Windows => "Windows",
+            Os::Linux => "Linux",
+            Os::MacOs => "macOS",
+            Os::Ios => "iOS",
+            Os::Android => "Android",
+        }
+        .to_string(),
+        gpu: profile.gpu.map(|g| format!("{:?}", g.vendor)),
+    })
+}
+
+/// Rank models for the current system and return recommendations.
+#[tauri::command]
+pub fn rank_models() -> Result<Vec<ModelRecommendation>, String> {
+    let profile = hardware::probe_system();
+    let ranked = recommendation::rank_recommendations(&profile);
+
+    Ok(ranked
+        .into_iter()
+        .map(|scored| {
+            let downloaded = kon_transcription::is_downloaded(&scored.entry.id);
+            ModelRecommendation {
+                id: scored.entry.id.as_str().to_string(),
+                display_name: scored.entry.display_name,
+                disk_size_mb: scored.entry.disk_size.0,
+                ram_required_mb: scored.entry.ram_required.0,
+                description: scored.entry.description,
+                score: scored.score,
+                reason: scored.reason,
+                is_downloaded: downloaded,
+            }
+        })
+        .collect())
+}

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;

src-tauri/src/lib.rs

@@ -70,6 +70,9 @@ pub fn run() {
             commands::windows::open_viewer_window,
             // Clipboard
             commands::clipboard::copy_to_clipboard,
+            // Hardware
+            commands::hardware::probe_system,
+            commands::hardware::rank_models,
             // LLM stubs
             commands::llm::download_llm_model,
             commands::llm::check_llm_model,