feat: Add initial Svelte frontend for ESP32 system monitoring and reboot control.

Provider/frontend/src/lib/api.js

@@ -0,0 +1,35 @@
+/**
+ * API layer for Calendink Provider ESP32-S3 dashboard.
+ *
+ * VITE_API_BASE controls the backend URL:
+ * - Development (PC): "http://<ESP32_IP>" (set in .env.development)
+ * - Production (ESP32): "" (empty = relative URLs, same origin)
+ */
+
+const API_BASE = import.meta.env.VITE_API_BASE || '';
+
+/**
+ * Fetch system information from the ESP32.
+ * @returns {Promise<{chip: string, freeHeap: number, uptime: number, firmware: string, connection: string}>}
+ */
+export async function getSystemInfo() {
+    const res = await fetch(`${API_BASE}/api/system/info`);
+    if (!res.ok) {
+        throw new Error(`HTTP ${res.status}: ${res.statusText}`);
+    }
+    return res.json();
+}
+
+/**
+ * Send a reboot command to the ESP32.
+ * @returns {Promise<{message: string}>}
+ */
+export async function reboot() {
+    const res = await fetch(`${API_BASE}/api/system/reboot`, {
+        method: 'POST',
+    });
+    if (!res.ok) {
+        throw new Error(`HTTP ${res.status}: ${res.statusText}`);
+    }
+    return res.json();
+}