feat(updater): in-app dragonxd updater + browse-all-releases

Add a full-node daemon updater (util/DaemonUpdater + daemon_download_dialog)
reachable from Settings -> NODE & SECURITY: downloads/verifies (SHA-256 +
enforced ed25519 signature) and atomically installs the latest dragonxd from
the project Gitea, with a "Restart daemon now" step. Add a shared "Browse all
releases..." picker (release_list_view) to both the miner and daemon updaters
so users can pin older/pre-release builds. Pure no-I/O cores
(daemon_updater_core / xmrig_updater_core) are unit-tested; sign-daemon-release.sh
signs release archives offline.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/util/xmrig_updater.h

@@ -38,7 +38,10 @@ struct XmrigReleaseAsset {
 struct XmrigRelease {
     bool ok = false;
     std::string tag;                       // e.g. "v1.0.0"
+    std::string name;                      // human title (e.g. "DRG-XMRig v6.25.3")
     std::string body;                      // release notes markdown (holds the checksum blocks)
+    bool prerelease = false;               // marked pre-release on the Gitea release
+    std::string publishedAt;               // ISO-8601 publish timestamp (date shown in the UI)
     std::vector<XmrigReleaseAsset> assets;
     std::string error;
 };
@@ -61,6 +64,10 @@ inline constexpr bool        kXmrigRequireSignature = true;   // enforced: refus
 // Parse the Gitea GET /releases/latest JSON into an XmrigRelease (ok=false + error on failure).
 XmrigRelease parseXmrigRelease(const std::string& json);
 
+// Parse the Gitea GET /releases (array) JSON into the list of releases, newest first, skipping
+// drafts. Empty on parse failure. Lets the user browse + pin a specific (or pre-release) version.
+std::vector<XmrigRelease> parseXmrigReleaseList(const std::string& json);
+
 // The asset-name token for the host platform: "linux-x64", "win-x64", "macos-x64",
 // "macos-arm64", or "" if unknown/unsupported.
 std::string currentXmrigPlatformToken();
@@ -102,6 +109,8 @@ public:
         UpToDate,
         UpdateAvailable,
         Unavailable,    // no miner build is published for this platform (terminal, not an error)
+        Listing,        // fetching the full release list (Browse all releases)
+        ReleaseList,    // release list fetched; awaiting the user's pick
         Downloading,
         Verifying,
         Extracting,
@@ -124,6 +133,9 @@ public:
     // Gitea releases API for the DRG-XMRig fork.
     static constexpr const char* kApiUrl =
         "https://git.dragonx.is/api/v1/repos/DragonX/drg-xmrig/releases/latest";
+    // Full release list (newest first, includes pre-releases) for the "Browse all releases" picker.
+    static constexpr const char* kReleasesUrl =
+        "https://git.dragonx.is/api/v1/repos/DragonX/drg-xmrig/releases?limit=50";
 
     XmrigUpdater() = default;
     ~XmrigUpdater();
@@ -136,10 +148,21 @@ public:
     void startCheck(const std::string& installedTag);
 
     // Download → verify archive → extract (flatten) → verify binary → install into `targetDir` on a
-    // background thread. Re-fetches the release so it is self-contained. End state: Done / Failed.
-    // On Done, getProgress().latest_tag is the version that should be persisted as the installed tag.
+    // background thread. Re-fetches the latest release so it is self-contained. End state: Done /
+    // Failed. On Done, getProgress().latest_tag is the version that should be persisted as installed.
     void startInstall(const std::string& targetDir);
 
+    // Fetch the full release list on a background thread (for "Browse all releases"). End state:
+    // ReleaseList (then getReleases() holds the list, newest first) / Failed.
+    void startListReleases();
+
+    // Snapshot of the release list fetched by startListReleases().
+    std::vector<XmrigRelease> getReleases() const;
+
+    // Install a SPECIFIC release (chosen from the browse list) into `targetDir` — same verify/extract
+    // path as startInstall, but pinned to `release` instead of latest. End state: Done / Failed.
+    void startInstallRelease(const std::string& targetDir, XmrigRelease release);
+
     void cancel();
     Progress getProgress() const;
     bool isDone() const;   // true once the worker reached a terminal state (Done/Failed/Unavailable)
@@ -151,13 +174,16 @@ public:
 
 private:
     void runCheck(std::string installedTag);
+    void runListReleases();
     void runInstall(std::string targetDir);
+    void installResolved(const std::string& targetDir, const XmrigRelease& rel);  // shared install body
     void setProgress(State state, const std::string& text, double done = 0, double total = 0);
     bool downloadToFile(const std::string& url, const std::string& destPath);
     std::string httpGet(const std::string& url);
 
     mutable std::mutex mutex_;
     Progress progress_;
+    std::vector<XmrigRelease> releases_;
     std::atomic<bool> cancel_requested_{false};
     std::atomic<bool> worker_running_{false};
     std::thread worker_;