feat: implement server self-upgrade functionality

- Added update service to fetch the latest server release from GitHub.
- Implemented server upgrade scheduling and execution logic.
- Created platform-specific restart mechanisms for Unix and Windows.
- Introduced API endpoints for fetching the latest release and triggering upgrades.
- Developed UI components for version upgrade modal, including loading and error states.
- Updated documentation to reflect new upgrade features and instructions.
- Refactored settings types to streamline interface definitions.

atsf_server/service/update_test.go

@@ -0,0 +1,65 @@
+package service
+
+import (
+	"atsflare/common"
+	"testing"
+)
+
+func TestIsVersionNewer(t *testing.T) {
+	testCases := []struct {
+		name     string
+		current  string
+		latest   string
+		expected bool
+	}{
+		{name: "newer patch", current: "v1.2.3", latest: "v1.2.4", expected: true},
+		{name: "same version", current: "v1.2.3", latest: "v1.2.3", expected: false},
+		{name: "older remote", current: "v1.3.0", latest: "v1.2.9", expected: false},
+		{name: "double digit segment", current: "v1.9.9", latest: "v1.10.0", expected: true},
+		{name: "dev build", current: "dev", latest: "v0.4.0", expected: true},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			actual := isVersionNewer(testCase.current, testCase.latest)
+			if actual != testCase.expected {
+				t.Fatalf("unexpected compare result: current=%s latest=%s actual=%v expected=%v", testCase.current, testCase.latest, actual, testCase.expected)
+			}
+		})
+	}
+}
+
+func TestBuildLatestServerReleaseView(t *testing.T) {
+	originalVersion := common.Version
+	common.Version = "v0.4.0"
+	t.Cleanup(func() {
+		common.Version = originalVersion
+		serverUpgradeState.Lock()
+		serverUpgradeState.inProgress = false
+		serverUpgradeState.Unlock()
+	})
+
+	serverUpgradeState.Lock()
+	serverUpgradeState.inProgress = true
+	serverUpgradeState.Unlock()
+
+	view := buildLatestServerReleaseView(&githubReleaseResponse{
+		TagName:     "v0.5.0",
+		Body:        "release notes",
+		HTMLURL:     "https://github.com/Rain-kl/ATSFlare/releases/tag/v0.5.0",
+		PublishedAt: "2026-03-11T00:00:00Z",
+	})
+
+	if view.CurrentVersion != "v0.4.0" {
+		t.Fatalf("unexpected current version: %s", view.CurrentVersion)
+	}
+	if !view.HasUpdate {
+		t.Fatal("expected has_update to be true")
+	}
+	if !view.InProgress {
+		t.Fatal("expected in_progress to reflect upgrade state")
+	}
+	if view.TagName != "v0.5.0" {
+		t.Fatalf("unexpected tag name: %s", view.TagName)
+	}
+}