Implement SyncWarden v0.1.0

Full Syncthing tray wrapper with:
- System tray with 5 icon states (idle/syncing/paused/error/disconnected)
- Syncthing REST API client with auto-discovered API key
- Long-polling event listener for real-time status
- Transfer rate monitoring, folder tracking, recent files, conflict counting
- Full context menu with folders, recent files, settings toggles
- Embedded admin panel binary (webview, requires CGO)
- OS notifications via beeep (per-event configurable)
- Syncthing process management with auto-restart
- Cross-platform installer with autostart
- CI pipeline for Linux (.deb + .tar.gz) and Windows (.zip)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/monitor/recent.go

@@ -0,0 +1,49 @@
+package monitor
+
+import (
+	"sync"
+	"time"
+)
+
+const maxRecentFiles = 10
+
+// RecentTracker maintains a ring buffer of recently synced files.
+type RecentTracker struct {
+	mu    sync.Mutex
+	files []RecentFile
+}
+
+// NewRecentTracker creates a new recent files tracker.
+func NewRecentTracker() *RecentTracker {
+	return &RecentTracker{
+		files: make([]RecentFile, 0, maxRecentFiles),
+	}
+}
+
+// Add records a newly synced file.
+func (rt *RecentTracker) Add(name, folder string) {
+	rt.mu.Lock()
+	defer rt.mu.Unlock()
+
+	rf := RecentFile{
+		Name:      name,
+		Folder:    folder,
+		Timestamp: time.Now(),
+	}
+
+	// Prepend (most recent first)
+	rt.files = append([]RecentFile{rf}, rt.files...)
+	if len(rt.files) > maxRecentFiles {
+		rt.files = rt.files[:maxRecentFiles]
+	}
+}
+
+// Files returns a snapshot of recent files (most recent first).
+func (rt *RecentTracker) Files() []RecentFile {
+	rt.mu.Lock()
+	defer rt.mu.Unlock()
+
+	out := make([]RecentFile, len(rt.files))
+	copy(out, rt.files)
+	return out
+}