feat: 同步 design/ 设计系统(含 iPad tablet kit) + 架构任务拆分(todo/)

design/ 同步自最新设计导出，新增 ui_kits/tablet/ 平板分栏布局；todo/ 录入 18 个并行实施任务。

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

design/flutter/widgets/status_pill.dart

@@ -0,0 +1,45 @@
+// status_pill.dart — 状态胶囊(色点 + 文字)。不用 emoji。
+// 对应 React UI Kit 的 .pill / 徽章。
+import 'package:flutter/material.dart';
+import '../pangolin_theme.dart';
+
+enum PangolinStatus { connected, connecting, error, neutral, pro }
+
+class StatusPill extends StatelessWidget {
+  const StatusPill({super.key, required this.label, this.status = PangolinStatus.neutral});
+  final String label;
+  final PangolinStatus status;
+
+  @override
+  Widget build(BuildContext context) {
+    final c = context.pangolin;
+    late final Color bg, fg, dot;
+    bool showDot = true;
+    switch (status) {
+      case PangolinStatus.connected:
+        bg = c.successSubtle; fg = c.success; dot = c.success; break;
+      case PangolinStatus.connecting:
+        bg = c.warningSubtle; fg = c.warning; dot = c.warning; break;
+      case PangolinStatus.error:
+        bg = c.dangerSubtle; fg = c.danger; dot = c.danger; break;
+      case PangolinStatus.pro:
+        bg = c.accent; fg = c.fgOnAccent; dot = c.fgOnAccent; showDot = false; break;
+      case PangolinStatus.neutral:
+        bg = c.bgSubtle; fg = c.fg2; dot = c.fg3; break;
+    }
+    return Container(
+      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
+      decoration: BoxDecoration(color: bg, borderRadius: BorderRadius.circular(PangolinRadius.full)),
+      child: Row(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          if (showDot) ...[
+            Container(width: 7, height: 7, decoration: BoxDecoration(color: dot, shape: BoxShape.circle)),
+            const SizedBox(width: 7),
+          ],
+          Text(label, style: PangolinText.caption.copyWith(color: fg, fontWeight: FontWeight.w600)),
+        ],
+      ),
+    );
+  }
+}