fix: properly reset console spy array in completion tests

Use array.length = 0 instead of reassignment to maintain spy reference

Co-authored-by: jwulf <406975+jwulf@users.noreply.github.com>

Author: Copilot

tests/unit/completion.test.ts

@@ -146,13 +146,13 @@ describe('Completion Module', () => {
     const output = consoleLogSpy.join('\n');
     assert.ok(output.includes('# c8ctl bash completion'));
 
-    consoleLogSpy = [];
+    consoleLogSpy.length = 0;
     showCompletion('Zsh');
 
     const output2 = consoleLogSpy.join('\n');
     assert.ok(output2.includes('#compdef c8ctl c8'));
 
-    consoleLogSpy = [];
+    consoleLogSpy.length = 0;
     showCompletion('FiSh');
 
     const output3 = consoleLogSpy.join('\n');