feat: add svelte web workspace shell

apps/web/src/features/auth/ServerLogin.svelte

@@ -0,0 +1,28 @@
+<script lang="ts">
+  import { createEventDispatcher } from 'svelte';
+
+  export let apiBase: string;
+
+  const dispatch = createEventDispatcher<{ serverChange: { apiBase: string } }>();
+  let server = apiBase;
+
+  function saveServer() {
+    const normalized = normalizeServer(server);
+    server = normalized;
+    dispatch('serverChange', { apiBase: normalized });
+  }
+
+  function normalizeServer(value: string) {
+    const trimmed = value.trim();
+    if (trimmed.startsWith('http://') || trimmed.startsWith('https://')) {
+      return trimmed;
+    }
+    return `http://${trimmed}`;
+  }
+</script>
+
+<form aria-label="服务器登录" class="server-login" on:submit|preventDefault={saveServer}>
+  <label for="server-address">服务器 IP 或域名</label>
+  <input id="server-address" name="server" bind:value={server} placeholder="http://localhost:8080" />
+  <button type="submit">保存服务器</button>
+</form>