fix: use obviously-fake key in MaskKey test fixture

Replace the genuine-looking key used as input to the MaskKey test
with an obviously synthetic 32-char string of the same shape, so
the fixture cannot be mistaken for a credential. Also add .claude/
to .gitignore to keep agent state out of the repo.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: chris-anstey-runware

.gitignore

@@ -3,3 +3,4 @@ dist/
 .DS_Store
 *.exe
 outputs/
+.claude/

internal/config/config_test.go

@@ -13,7 +13,7 @@ func TestMaskKey(t *testing.T) {
 		input    string
 		expected string
 	}{
-		{"gcuTZLxvUU3tb9TGfyAUkGiLmFS2Dvqn", "gcuT****Dvqn"},
+		{"abcdEFGHijklMNOPqrstUVWXyz0123456", "abcd****3456"},
 		{"short", "****"},
 		{"12345678", "****"},
 		{"123456789", "1234****6789"},