```

refactor: 重命名项目名称从"体己"到"康康"

将整个项目的目录结构从"体己"重命名为"康康"，包括所有源代码文件、
资源文件、测试文件以及Xcode项目配置文件。此更改涉及项目中所有的
文件路径和应用入口点(App/TijiApp.swift → App/KangkangApp.swift)。
```

康康Tests/FileVaultTests.swift

@@ -0,0 +1,59 @@
+import Testing
+import UIKit
+@testable import 体己
+
+struct FileVaultTests {
+
+    private func makeIsolatedVault() throws -> FileVault {
+        let temp = FileManager.default.temporaryDirectory
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+        return try FileVault(rootURL: temp)
+    }
+
+    private func makeTestImage() -> UIImage {
+        let size = CGSize(width: 16, height: 16)
+        let renderer = UIGraphicsImageRenderer(size: size)
+        return renderer.image { ctx in
+            UIColor.red.setFill()
+            ctx.fill(CGRect(origin: .zero, size: size))
+        }
+    }
+
+    @Test func writeAndReadJPEGRoundtrip() throws {
+        let vault = try makeIsolatedVault()
+        defer { try? FileManager.default.removeItem(at: vault.rootURL) }
+        let image = makeTestImage()
+
+        let saved = try vault.writeJPEG(image, quality: 0.8)
+
+        #expect(saved.bytes > 0)
+        #expect(saved.relativePath.hasSuffix(".jpg"))
+
+        let loaded = try vault.loadImage(relativePath: saved.relativePath)
+        #expect(loaded.size != .zero)
+    }
+
+    @Test func removeMakesFileGone() throws {
+        let vault = try makeIsolatedVault()
+        defer { try? FileManager.default.removeItem(at: vault.rootURL) }
+        let saved = try vault.writeJPEG(makeTestImage())
+
+        try vault.remove(relativePath: saved.relativePath)
+
+        #expect(throws: (any Error).self) {
+            _ = try vault.loadImage(relativePath: saved.relativePath)
+        }
+    }
+
+    @Test func wipeRemovesAllFiles() throws {
+        let vault = try makeIsolatedVault()
+        defer { try? FileManager.default.removeItem(at: vault.rootURL) }
+        let a = try vault.writeJPEG(makeTestImage())
+        let b = try vault.writeJPEG(makeTestImage())
+
+        try vault.wipe()
+
+        #expect(throws: (any Error).self) { _ = try vault.loadImage(relativePath: a.relativePath) }
+        #expect(throws: (any Error).self) { _ = try vault.loadImage(relativePath: b.relativePath) }
+    }
+}