feat(converter): add native release update checks

README.md

@@ -71,6 +71,13 @@ rollback themselves. The macOS window appears in the Dock and Cmd-Tab, follows
 the system language by default, and can switch between Simplified Chinese and
 English in Settings.
 
+Both native workbenches expose **About & Updates**. The first launch on each
+local calendar day makes at most one non-blocking request to the official
+`MHToolkit/mh-save-sync` latest-release endpoint; users may also check
+manually. An unavailable GitHub connection never blocks conversion. A newer
+release dialog shows its version, publication date, release notes, and official
+link. No save bytes or selected paths are sent with this request.
+
 The workbenches provide four **guided but non-blocking** stages: input and
 inspection, optional shared data, Dry Run, then write or rollback. Completing
 one stage reveals the recommended next action (for example, inspect then

README.zh-CN.md

@@ -53,6 +53,11 @@ JSON 报告；不会在 UI 内重写字节转换、备份、manifest、模拟器
 macOS 窗口会正常出现于 Dock 和 Cmd-Tab；默认跟随系统语言，也可在设置中切换简体中文或
 English。
 
+两个原生工作台都提供“**关于与更新**”。每个本地自然日首次启动最多向
+`MHToolkit/mh-save-sync` 官方 latest-release 接口发起一次非阻塞请求，也可手动检查；
+GitHub 不可访问时绝不会阻塞转换。发现新版时会显示版本、发布日期、Release 说明和官方
+链接。该请求不会上传任何存档字节或用户所选路径。
+
 工作台提供四个**有引导、但不强制**的阶段：输入与检查、可选共享数据、Dry Run、写入或
 回滚。完成一个阶段后会显示推荐的下一步操作（例如检查完成后配置可选数据），但玩家仍可
 返回前一阶段，或跳过可选组件。该引导不会额外执行任何转换。

apps/mh3g-save-converter-macos/README.md

@@ -31,6 +31,23 @@ Normal conversion uses a single-file manifest; compatibility repair uses
 `.mh3g-compatibility-repair-<UUID>.json` and `rollback-repair`. Quit Nemessix,
 Azahar, and Cemu before any write or rollback.
 
+The optional housekeeper gallery/movie migration never creates or replaces a
+shared `system` from the 3DS file alone. Select both the 3DS source `system` and
+an existing initialized Cemu `system`; the converter unions only the known
+gallery/movie flags and preserves every other Cemu byte, including data shared
+by the other character slots.
+
+## Updates
+
+The About & Updates section resolves the latest stable tag through the official
+`MHToolkit/mh-save-sync` GitHub release page and reads its official Atom release
+feed. This path does not consume the shared anonymous GitHub API quota; the
+Release API remains a fallback. The first launch on each local calendar day
+makes at most one silent attempt. A blocked or unavailable GitHub connection
+never blocks the window or any local conversion; manual checks show the error
+and may be retried. When a newer release exists, the app shows its title,
+publication date, release notes, and official release link.
+
 ## Local verification
 
 ```bash

apps/mh3g-save-converter-macos/README.zh-CN.md

@@ -23,6 +23,19 @@ sidecar 并展示 JSON 报告，不在 Swift 中重复实现存档转换。
 使用 `.mh3g-compatibility-repair-<UUID>.json` 并通过 `rollback-repair` 总体回滚。
 执行写入或回滚前必须退出 Nemessix、Azahar 和 Cemu。
 
+可选的管家画廊/动画迁移不会只凭 3DS `system` 新建或整文件覆盖共享
+`system`。必须同时选择 3DS 源 `system` 和已存在、已初始化的 Cemu `system`；
+转换器只合并已知画廊/动画标记，其他 Cemu 字节（包括其他角色槽位共享数据）
+全部保留。
+
+## 更新检查
+
+“关于与更新”会通过 `MHToolkit/mh-save-sync` 官方 GitHub Release 页面确认最新
+正式版 tag，并读取官方 Atom Release feed。该主路径不消耗共享的 GitHub 匿名
+API 配额，Release API 仅作为备用。每个本地自然日首次启动最多静默尝试一次；
+GitHub 无法访问时不会阻塞窗口，也不会影响任何本地转换。手动检查会展示错误并
+允许重试；发现新版本时会显示版本名、发布日期、Release 说明和官方发布链接。
+
 ## 本地验证
 
 ```bash

apps/mh3g-save-converter-macos/Sources/ConverterPresentation/Localization.swift

@@ -292,6 +292,20 @@ public enum ConverterCopy {
         "WorkflowState.Failure": "操作失败",
         "Settings.BundledSidecar": "打包时使用内置 sidecar",
         "Settings.Development": "开发版本",
+        "Update.About": "关于与更新",
+        "Update.CurrentVersion": "当前版本",
+        "Update.Check": "检查更新",
+        "Update.Checking": "正在连接 GitHub…",
+        "Update.UpToDate": "已经是最新版（GitHub：%@）",
+        "Update.Available": "发现新版本 %@，请在弹窗中查看更新说明。",
+        "Update.Failed": "无法检查更新",
+        "Update.NetworkNote": "每天首次启动会静默检查一次 GitHub Release；网络不可用时不会阻塞或影响任何本地存档操作。也可以随时手动重试。",
+        "Update.AvailableTitle": "发现新版本",
+        "Update.VersionSummary": "当前 %@ · 最新 %@",
+        "Update.ReleaseNotes": "更新说明",
+        "Update.NoReleaseNotes": "该版本未提供更新说明。",
+        "Update.Later": "稍后",
+        "Update.OpenRelease": "打开发布页面",
     ]
 
     private static let english: [String: String] = [
@@ -482,6 +496,20 @@ public enum ConverterCopy {
         "WorkflowState.Failure": "Operation failed",
         "Settings.BundledSidecar": "Bundled sidecar when packaged",
         "Settings.Development": "development",
+        "Update.About": "About & Updates",
+        "Update.CurrentVersion": "Current version",
+        "Update.Check": "Check for Updates",
+        "Update.Checking": "Contacting GitHub…",
+        "Update.UpToDate": "You are up to date (GitHub: %@)",
+        "Update.Available": "Version %@ is available. Review its release notes in the update window.",
+        "Update.Failed": "Unable to check for updates",
+        "Update.NetworkNote": "The first launch each day silently checks GitHub Releases once. An unavailable network never blocks or changes any local save operation, and you can retry manually at any time.",
+        "Update.AvailableTitle": "Update Available",
+        "Update.VersionSummary": "Current %@ · Latest %@",
+        "Update.ReleaseNotes": "Release notes",
+        "Update.NoReleaseNotes": "No release notes were provided for this version.",
+        "Update.Later": "Later",
+        "Update.OpenRelease": "Open Release Page",
     ]
 
     /// The complete set of copy IDs rendered by the SwiftUI workbench.  Tests

apps/mh3g-save-converter-macos/Sources/ConverterPresentation/UpdateChecking.swift

@@ -0,0 +1,268 @@
+import Foundation
+
+public struct ConverterSemanticVersion: Comparable, Equatable, Sendable, CustomStringConvertible {
+    public let components: [Int]
+
+    public init?(_ value: String) {
+        let normalized = value
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+            .trimmingPrefix("v")
+            .split(separator: "+", maxSplits: 1, omittingEmptySubsequences: true)[0]
+            .split(separator: "-", maxSplits: 1, omittingEmptySubsequences: true)[0]
+        let parts = normalized.split(separator: ".", omittingEmptySubsequences: false)
+        guard !parts.isEmpty,
+              parts.allSatisfy({ !$0.isEmpty && $0.allSatisfy(\.isNumber) }),
+              parts.allSatisfy({ Int($0) != nil })
+        else {
+            return nil
+        }
+        components = parts.map { Int($0)! }
+    }
+
+    public static func < (lhs: Self, rhs: Self) -> Bool {
+        let count = max(lhs.components.count, rhs.components.count)
+        for index in 0..<count {
+            let left = index < lhs.components.count ? lhs.components[index] : 0
+            let right = index < rhs.components.count ? rhs.components[index] : 0
+            if left != right {
+                return left < right
+            }
+        }
+        return false
+    }
+
+    public static func == (lhs: Self, rhs: Self) -> Bool {
+        !(lhs < rhs) && !(rhs < lhs)
+    }
+
+    public var description: String {
+        components.map(String.init).joined(separator: ".")
+    }
+}
+
+public struct GitHubConverterRelease: Codable, Equatable, Identifiable, Sendable {
+    public let tagName: String
+    public let name: String?
+    public let body: String?
+    public let htmlURL: URL
+    public let publishedAt: String?
+    public let draft: Bool
+    public let prerelease: Bool
+
+    public var id: String { tagName }
+
+    public var isOfficialStableRelease: Bool {
+        !draft
+            && !prerelease
+            && htmlURL.scheme == "https"
+            && htmlURL.host?.lowercased() == "github.com"
+            && htmlURL.path.hasPrefix("/MHToolkit/mh-save-sync/releases/")
+    }
+
+    public init(
+        tagName: String,
+        name: String?,
+        body: String?,
+        htmlURL: URL,
+        publishedAt: String?,
+        draft: Bool,
+        prerelease: Bool
+    ) {
+        self.tagName = tagName
+        self.name = name
+        self.body = body
+        self.htmlURL = htmlURL
+        self.publishedAt = publishedAt
+        self.draft = draft
+        self.prerelease = prerelease
+    }
+
+    enum CodingKeys: String, CodingKey {
+        case tagName = "tag_name"
+        case name
+        case body
+        case htmlURL = "html_url"
+        case publishedAt = "published_at"
+        case draft
+        case prerelease
+    }
+}
+
+public enum ConverterUpdateDecision: Equatable, Sendable {
+    case updateAvailable
+    case upToDate
+    case invalidVersion
+
+    public static func decide(current: String, latest: String) -> Self {
+        guard let currentVersion = ConverterSemanticVersion(current),
+              let latestVersion = ConverterSemanticVersion(latest)
+        else {
+            return .invalidVersion
+        }
+        return currentVersion < latestVersion ? .updateAvailable : .upToDate
+    }
+}
+
+public enum GitHubReleaseAtomFeed {
+    public static func stableRelease(from data: Data, expectedReleaseURL: URL) throws -> GitHubConverterRelease {
+        guard isOfficialTagURL(expectedReleaseURL),
+              let tagName = expectedReleaseURL.lastPathComponent.removingPercentEncoding,
+              ConverterSemanticVersion(tagName) != nil
+        else {
+            throw GitHubReleaseAtomFeedError.invalidReleaseURL
+        }
+
+        let delegate = GitHubReleaseAtomParser()
+        let parser = XMLParser(data: data)
+        parser.delegate = delegate
+        guard parser.parse(), parser.parserError == nil else {
+            throw GitHubReleaseAtomFeedError.invalidXML
+        }
+        guard let entry = delegate.entries.first(where: {
+            $0.link?.absoluteString == expectedReleaseURL.absoluteString
+        }) else {
+            throw GitHubReleaseAtomFeedError.releaseNotFound
+        }
+
+        let release = GitHubConverterRelease(
+            tagName: tagName,
+            name: entry.title.nilIfBlank,
+            body: plainText(fromHTML: entry.content).nilIfBlank,
+            htmlURL: expectedReleaseURL,
+            publishedAt: entry.updated.nilIfBlank,
+            draft: false,
+            prerelease: false
+        )
+        guard release.isOfficialStableRelease else {
+            throw GitHubReleaseAtomFeedError.invalidReleaseURL
+        }
+        return release
+    }
+
+    public static func isOfficialTagURL(_ url: URL) -> Bool {
+        url.scheme == "https"
+            && url.host?.lowercased() == "github.com"
+            && url.query == nil
+            && url.fragment == nil
+            && url.path.hasPrefix("/MHToolkit/mh-save-sync/releases/tag/")
+            && url.pathComponents.count == 6
+    }
+
+    private static func plainText(fromHTML html: String) -> String {
+        var text = html.replacingOccurrences(
+            of: #"(?i)<li(?:\s[^>]*)?>"#,
+            with: "• ",
+            options: .regularExpression
+        )
+        text = text.replacingOccurrences(
+            of: #"(?i)<br\s*/?>|</li\s*>|</p\s*>|</h[1-6]\s*>|</blockquote\s*>|</pre\s*>"#,
+            with: "\n",
+            options: .regularExpression
+        )
+        text = text.replacingOccurrences(of: #"<[^>]+>"#, with: "", options: .regularExpression)
+        return text
+            .split(whereSeparator: \Character.isNewline)
+            .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+            .filter { !$0.isEmpty }
+            .joined(separator: "\n")
+            .prefix(32_000)
+            .description
+    }
+}
+
+private enum GitHubReleaseAtomFeedError: Error {
+    case invalidReleaseURL
+    case invalidXML
+    case releaseNotFound
+}
+
+private final class GitHubReleaseAtomParser: NSObject, XMLParserDelegate {
+    struct Entry {
+        var title = ""
+        var updated = ""
+        var content = ""
+        var link: URL?
+    }
+
+    private(set) var entries: [Entry] = []
+    private var currentEntry: Entry?
+    private var capturedElement: String?
+    private var characters = ""
+
+    func parser(
+        _ parser: XMLParser,
+        didStartElement elementName: String,
+        namespaceURI: String?,
+        qualifiedName qName: String?,
+        attributes attributeDict: [String: String] = [:]
+    ) {
+        if elementName == "entry" {
+            currentEntry = Entry()
+            return
+        }
+        guard currentEntry != nil else { return }
+        if elementName == "link",
+           attributeDict["rel"] == "alternate",
+           let href = attributeDict["href"],
+           let url = URL(string: href)
+        {
+            currentEntry?.link = url
+        } else if elementName == "title" || elementName == "updated" || elementName == "content" {
+            capturedElement = elementName
+            characters = ""
+        }
+    }
+
+    func parser(_ parser: XMLParser, foundCharacters string: String) {
+        guard capturedElement != nil else { return }
+        characters += string
+    }
+
+    func parser(
+        _ parser: XMLParser,
+        didEndElement elementName: String,
+        namespaceURI: String?,
+        qualifiedName qName: String?
+    ) {
+        if elementName == capturedElement {
+            switch elementName {
+            case "title":
+                currentEntry?.title = characters.trimmingCharacters(in: .whitespacesAndNewlines)
+            case "updated":
+                currentEntry?.updated = characters.trimmingCharacters(in: .whitespacesAndNewlines)
+            case "content":
+                currentEntry?.content = characters
+            default:
+                break
+            }
+            capturedElement = nil
+            characters = ""
+        }
+        if elementName == "entry", let currentEntry {
+            entries.append(currentEntry)
+            self.currentEntry = nil
+        }
+    }
+}
+
+public enum DailyUpdateCheckGate {
+    public static func shouldCheck(
+        lastAttempt: Date?,
+        now: Date,
+        calendar: Calendar = .current
+    ) -> Bool {
+        guard let lastAttempt else { return true }
+        return !calendar.isDate(lastAttempt, inSameDayAs: now)
+    }
+}
+
+private extension String {
+    var nilIfBlank: String? {
+        let trimmed = trimmingCharacters(in: .whitespacesAndNewlines)
+        return trimmed.isEmpty ? nil : trimmed
+    }
+
+    func trimmingPrefix(_ prefix: Character) -> String {
+        first == prefix ? String(dropFirst()) : self
+    }
+}