Initial scaffold from M1 spike (tiletopia)

Tauri 2 + Svelte 5 + xterm.js + portable-pty. Single full-window
WSL terminal pane with clickable distro picker. M1 verified manually
on Windows: window opens, xterm.js renders, claude TUI works,
resize reflows cleanly.

Graduated from ~/claude/ideas/wsl-mux/ per the approved plan at
~/.claude/plans/imperative-coalescing-feigenbaum.md. See memory.md
for decisions, open TODOs, and the M2-M5 roadmap.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src-tauri/src/commands.rs

@@ -0,0 +1,57 @@
+//! Tauri command surface. Every JS-callable function lives here.
+
+use base64::{engine::general_purpose::STANDARD as B64, Engine as _};
+use tauri::AppHandle;
+
+use crate::pty::{list_wsl_distros, PaneId, PtyManager};
+
+#[tauri::command]
+pub async fn list_distros() -> Result<Vec<String>, String> {
+    list_wsl_distros().map_err(|e| e.to_string())
+}
+
+#[tauri::command]
+pub async fn spawn_pane(
+    app: AppHandle,
+    manager: tauri::State<'_, PtyManager>,
+    distro: Option<String>,
+    cwd: Option<String>,
+    cols: u16,
+    rows: u16,
+) -> Result<PaneId, String> {
+    manager
+        .spawn_wsl(app, distro, cwd, cols, rows)
+        .map_err(|e| e.to_string())
+}
+
+/// `data_b64` is base64-encoded UTF-8 bytes (xterm.js's `onData` emits
+/// strings; the frontend encodes before sending).
+#[tauri::command]
+pub async fn write_to_pane(
+    manager: tauri::State<'_, PtyManager>,
+    id: PaneId,
+    data_b64: String,
+) -> Result<(), String> {
+    let bytes = B64
+        .decode(data_b64.as_bytes())
+        .map_err(|e| format!("base64 decode: {e}"))?;
+    manager.write(id, &bytes).map_err(|e| e.to_string())
+}
+
+#[tauri::command]
+pub async fn resize_pane(
+    manager: tauri::State<'_, PtyManager>,
+    id: PaneId,
+    cols: u16,
+    rows: u16,
+) -> Result<(), String> {
+    manager.resize(id, cols, rows).map_err(|e| e.to_string())
+}
+
+#[tauri::command]
+pub async fn kill_pane(
+    manager: tauri::State<'_, PtyManager>,
+    id: PaneId,
+) -> Result<(), String> {
+    manager.kill(id).map_err(|e| e.to_string())
+}