feat: Kisani UI overhaul — brand identity, gallery, visual polish

- Rename app to Kisani (CFBundleDisplayName, xcodeproj → Kisani.xcodeproj)
- BackupView: kisani. wordmark + SwiftUI-drawn server logo mark (no asset,
  adaptive ink/bg), 206pt progress ring with active-state glow, 4-page
  swipeable ring (progress/pending/failed/uploaded), 4-metric stats strip,
  friendly NAS card (Home Server label), hamburger → AppMenuView sheet
- GalleryView: new NAS + local photo grid with source picker chip, 3-col
  lazy grid, ThumbnailCache, sync-status dots (green = backed up)
- MainTabView: Browse tab → Gallery tab; tab bar uses ultraThinMaterial
  blur background (systemGray3 icons, 9.5pt labels)
- All app icon sizes regenerated from 1024pt source via sips
- LANMonitor: nasReachable Bool?, checkNASReachability(host:port:) TCP ping
- project.yml: photo library usage description updated to Kisani branding

Co-Authored-By: Kutesir <kutesir@provoc.ug>
Co-Authored-By: Sentry <sentry@provoc.ug>

Services/ThumbnailCache.swift

@@ -0,0 +1,50 @@
+import UIKit
+
+final class ThumbnailCache {
+    static let shared = ThumbnailCache()
+
+    private let memory = NSCache<NSString, UIImage>()
+    private let diskDir: URL
+
+    private init() {
+        let caches = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)[0]
+        diskDir = caches.appendingPathComponent("NASThumb", isDirectory: true)
+        try? FileManager.default.createDirectory(at: diskDir, withIntermediateDirectories: true)
+        memory.countLimit = 300
+        memory.totalCostLimit = 80 * 1024 * 1024 // 80 MB
+    }
+
+    func get(for path: String) -> UIImage? {
+        let key = cacheKey(path)
+        if let img = memory.object(forKey: key as NSString) { return img }
+        let url = diskDir.appendingPathComponent(key)
+        guard let data = try? Data(contentsOf: url),
+              let img = UIImage(data: data) else { return nil }
+        memory.setObject(img, forKey: key as NSString, cost: data.count)
+        return img
+    }
+
+    func set(_ image: UIImage, for path: String) {
+        let key = cacheKey(path)
+        let data = image.jpegData(compressionQuality: 0.7) ?? Data()
+        memory.setObject(image, forKey: key as NSString, cost: data.count)
+        let url = diskDir.appendingPathComponent(key)
+        try? data.write(to: url, options: .atomic)
+    }
+
+    private func cacheKey(_ path: String) -> String {
+        path
+            .replacingOccurrences(of: "/", with: "_")
+            .replacingOccurrences(of: ":", with: "-")
+    }
+}
+
+extension UIImage {
+    func thumbnailScaled(to size: CGFloat) -> UIImage {
+        let scale = min(size / self.size.width, size / self.size.height)
+        guard scale < 1 else { return self }
+        let newSize = CGSize(width: self.size.width * scale, height: self.size.height * scale)
+        let renderer = UIGraphicsImageRenderer(size: newSize)
+        return renderer.image { _ in self.draw(in: CGRect(origin: .zero, size: newSize)) }
+    }
+}