Fix post-checkout hook installation failing in git worktrees

Sources/LucaCore/Core/FileManagerProtocols/GitHookInstallerFileManaging.swift

@@ -12,4 +12,5 @@ public protocol GitHookInstallerFileManaging {
     func readString(at url: URL) throws -> String
     func writeString(_ content: String, to url: URL) throws
     func setAttributes(_ attributes: [FileAttributeKey: Any], ofItemAtPath path: String) throws
+    func attributesOfItem(atPath path: String) throws -> [FileAttributeKey: Any]
 }

Sources/LucaCore/Core/GitHookInstaller/GitHookInstaller.swift

@@ -30,6 +30,12 @@ public struct GitHookInstaller {
             return
         }
 
+        // In a git worktree, `.git` is a file (not a directory) pointing to the main repo.
+        // Hooks live in the main repo; skip installation to avoid failing in a worktree context.
+        guard (try? fileManager.attributesOfItem(atPath: gitDirectory.path)[.type] as? FileAttributeType) == .typeDirectory else {
+            return
+        }
+
         let sourceHookPath = fileManager.homeDirectoryForCurrentUser
             .appending(components: Constants.toolFolder, "post-checkout")
 

Tests/Core/GitHookInstallerTests.swift

@@ -40,6 +40,22 @@ final class GitHookInstallerTests: XCTestCase {
         XCTAssertTrue(printer.printedMessages.isEmpty)
     }
 
+    // MARK: - Git Worktree
+
+    func test_installPostCheckoutHook_whenGitWorktree_doesNothing() throws {
+        // Given: `.git` is a file (worktree), not a directory
+        let currentDirectory = URL(fileURLWithPath: fileManager.currentDirectoryPath)
+        try fileManager.createDirectory(at: currentDirectory, withIntermediateDirectories: true)
+        let gitFile = currentDirectory.appending(component: ".git")
+        _ = fileManager.createFile(atPath: gitFile.path, contents: Data("gitdir: /some/main/repo/.git/worktrees/feature\n".utf8))
+
+        // When
+        try sut.installPostCheckoutHook()
+
+        // Then
+        XCTAssertTrue(printer.printedMessages.isEmpty)
+    }
+
     // MARK: - Source Hook Missing
 
     func test_installPostCheckoutHook_whenSourceHookMissing_printsWarning() throws {