Implement statistics tab aligned with Android and fix summary decode.

Add role-based analyse APIs, summary/daily UI with date range sheet, and flexible parsing for string refund amounts from the backend.

Co-authored-by: Cursor <cursoragent@cursor.com>

suixinkan/UI/Statistics/StatisticsPeriodButton.swift

@@ -0,0 +1,43 @@
+//
+//  StatisticsPeriodButton.swift
+//  suixinkan
+//
+
+import SnapKit
+import UIKit
+
+/// 数据统计周期 pill 按钮，对齐 Android `PeriodButton`。
+final class StatisticsPeriodButton: UIButton {
+
+    var periodTitle: String = "" {
+        didSet { setTitle(periodTitle, for: .normal) }
+    }
+
+    override var isSelected: Bool {
+        didSet { updateAppearance() }
+    }
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        setupUI()
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    private func setupUI() {
+        titleLabel?.font = .systemFont(ofSize: 14, weight: .medium)
+        layer.cornerRadius = 18
+        clipsToBounds = true
+        contentEdgeInsets = UIEdgeInsets(top: 6, left: 20, bottom: 6, right: 20)
+        updateAppearance()
+    }
+
+    private func updateAppearance() {
+        backgroundColor = isSelected ? UIColor(hex: 0x3B82F6) : UIColor(hex: 0xF3F4F6)
+        setTitleColor(isSelected ? .white : UIColor(hex: 0x4B5563), for: .normal)
+        titleLabel?.font = .systemFont(ofSize: 14, weight: isSelected ? .semibold : .medium)
+    }
+}