test: disable GPG signing in all test helpers

Prevent GPG signing prompts (including Yubikey activation) during test runs
by explicitly disabling commit.gpgsign and tag.gpgsign in all test repository
creation helpers.

Modified:
- tests/common/purgatory_helpers.rs: create_test_repo_with_commit()
- src/git/mod.rs: create_test_repo_with_commit()
- src/purgatory/helpers.rs: create_test_repo_with_commit()

All test repositories now have GPG signing disabled regardless of global
git configuration.

src/git/mod.rs

@@ -535,6 +535,17 @@ mod tests {
             .current_dir(&work_dir)
             .output()
             .unwrap();
+        // Disable GPG signing for tests (prevents yubikey prompts)
+        Command::new("git")
+            .args(["config", "commit.gpgsign", "false"])
+            .current_dir(&work_dir)
+            .output()
+            .unwrap();
+        Command::new("git")
+            .args(["config", "tag.gpgsign", "false"])
+            .current_dir(&work_dir)
+            .output()
+            .unwrap();
 
         // Create a file and commit
         fs::write(work_dir.join("README.md"), "# Test").unwrap();

src/purgatory/helpers.rs

@@ -534,6 +534,19 @@ mod tests {
             .output()
             .expect("Failed to set name");
 
+        // Disable GPG signing for tests (prevents yubikey prompts)
+        Command::new("git")
+            .args(["config", "commit.gpgsign", "false"])
+            .current_dir(work_dir.path())
+            .output()
+            .expect("Failed to disable commit.gpgsign");
+
+        Command::new("git")
+            .args(["config", "tag.gpgsign", "false"])
+            .current_dir(work_dir.path())
+            .output()
+            .expect("Failed to disable tag.gpgsign");
+
         // Create a commit
         std::fs::write(work_dir.path().join("file.txt"), "content").unwrap();
         Command::new("git")

tests/common/purgatory_helpers.rs

@@ -51,6 +51,10 @@ pub fn create_test_repo_with_commit(path: &Path, variant: CommitVariant) -> Resu
     // Configure git user for commits
     run_git(path, &["config", "user.email", "test@example.com"])?;
     run_git(path, &["config", "user.name", "Test User"])?;
+    
+    // Disable GPG signing for tests (prevents yubikey prompts)
+    run_git(path, &["config", "commit.gpgsign", "false"])?;
+    run_git(path, &["config", "tag.gpgsign", "false"])?;
 
     // Create a file based on variant
     let (filename, content) = match variant {