Add login flow, session routing, and MainTab shell aligned with reference UI.

Implement token-based root routing, Android-matched login screen, five-slot MainTabBar with scan action, and placeholder tab pages.

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

suixinkan/UI/Common/AgreementRowView.swift

@@ -0,0 +1,114 @@
+//
+//  AgreementRowView.swift
+//  suixinkan
+//
+
+import SnapKit
+import UIKit
+
+/// 协议勾选行，对应 Android `AgreementRow`。
+final class AgreementRowView: UIView, UITextViewDelegate {
+
+    private let checkButton = UIButton(type: .custom)
+    private let textView = UITextView()
+
+    var isChecked = false {
+        didSet { updateCheckboxImage() }
+    }
+
+    var onCheckedChange: (() -> Void)?
+    var onUserAgreementTap: (() -> Void)?
+    var onPrivacyPolicyTap: (() -> Void)?
+
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        setupUI()
+        setupConstraints()
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    private func setupUI() {
+        checkButton.addTarget(self, action: #selector(checkButtonTapped), for: .touchUpInside)
+        updateCheckboxImage()
+
+        textView.backgroundColor = .clear
+        textView.isEditable = false
+        textView.isScrollEnabled = false
+        textView.textContainerInset = .zero
+        textView.textContainer.lineFragmentPadding = 0
+        textView.delegate = self
+        textView.linkTextAttributes = [
+            .foregroundColor: AppColor.agreementLink,
+            .font: UIFont.systemFont(ofSize: 12, weight: .semibold),
+        ]
+        textView.attributedText = makeAgreementText()
+
+        addSubview(checkButton)
+        addSubview(textView)
+    }
+
+    private func setupConstraints() {
+        checkButton.snp.makeConstraints { make in
+            make.leading.top.equalToSuperview()
+            make.size.equalTo(18)
+        }
+
+        textView.snp.makeConstraints { make in
+            make.leading.equalTo(checkButton.snp.trailing).offset(8)
+            make.trailing.top.bottom.equalToSuperview()
+        }
+    }
+
+    private func updateCheckboxImage() {
+        let imageName = isChecked ? "icon_cb_privacy_selected" : "icon_cb_privacy_unselect"
+        checkButton.setImage(UIImage(named: imageName), for: .normal)
+    }
+
+    private func makeAgreementText() -> NSAttributedString {
+        let result = NSMutableAttributedString()
+        let normalAttributes: [NSAttributedString.Key: Any] = [
+            .font: UIFont.systemFont(ofSize: 12),
+            .foregroundColor: AppColor.text666,
+        ]
+        let linkFont = UIFont.systemFont(ofSize: 12, weight: .semibold)
+
+        result.append(NSAttributedString(string: "已阅读并同意", attributes: normalAttributes))
+        result.append(NSAttributedString(string: "《用户协议》", attributes: [
+            .font: linkFont,
+            .foregroundColor: AppColor.agreementLink,
+            .link: "tos",
+        ]))
+        result.append(NSAttributedString(string: "与", attributes: normalAttributes))
+        result.append(NSAttributedString(string: "《隐私政策》", attributes: [
+            .font: linkFont,
+            .foregroundColor: AppColor.agreementLink,
+            .link: "privacy",
+        ]))
+        return result
+    }
+
+    @objc private func checkButtonTapped() {
+        onCheckedChange?()
+    }
+
+    func textView(
+        _ textView: UITextView,
+        shouldInteractWith URL: URL,
+        in characterRange: NSRange,
+        interaction: UITextItemInteraction
+    ) -> Bool {
+        switch URL.absoluteString {
+        case "tos":
+            onUserAgreementTap?()
+        case "privacy":
+            onPrivacyPolicyTap?()
+        default:
+            break
+        }
+        return false
+    }
+}