```

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/ModelStoreTests.swift

@@ -0,0 +1,54 @@
+import Testing
+import Foundation
+@testable import 体己
+
+struct ModelStoreTests {
+
+    private func isolatedStore() throws -> ModelStore {
+        let temp = FileManager.default.temporaryDirectory
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+        return try ModelStore(rootURL: temp)
+    }
+
+    @Test func freshStoreReportsBothModelsMissing() throws {
+        let store = try isolatedStore()
+        defer { try? FileManager.default.removeItem(at: store.rootURL) }
+
+        #expect(store.isReady(.llm) == false)
+        #expect(store.isReady(.vl) == false)
+    }
+
+    @Test func markReadyAfterFolderCreated() throws {
+        let store = try isolatedStore()
+        defer { try? FileManager.default.removeItem(at: store.rootURL) }
+
+        let llmFolder = store.localURL(for: .llm)
+        try FileManager.default.createDirectory(at: llmFolder, withIntermediateDirectories: true)
+        let configURL = llmFolder.appendingPathComponent("config.json")
+        try "{}".write(to: configURL, atomically: true, encoding: .utf8)
+
+        #expect(store.isReady(.llm) == true)
+        #expect(store.isReady(.vl) == false)
+    }
+
+    @Test func totalBytesSumsExistingFiles() throws {
+        let store = try isolatedStore()
+        defer { try? FileManager.default.removeItem(at: store.rootURL) }
+
+        let folder = store.localURL(for: .llm)
+        try FileManager.default.createDirectory(at: folder, withIntermediateDirectories: true)
+        let data = Data(repeating: 0, count: 1024)
+        try data.write(to: folder.appendingPathComponent("a.bin"))
+        try data.write(to: folder.appendingPathComponent("b.bin"))
+
+        #expect(store.totalBytes(for: .llm) == 2048)
+    }
+
+    @Test func totalBytesReturnsZeroWhenFolderMissing() throws {
+        let store = try isolatedStore()
+        defer { try? FileManager.default.removeItem(at: store.rootURL) }
+
+        // 没创建任何 vl 目录
+        #expect(store.totalBytes(for: .vl) == 0)
+    }
+}