fix: add .context/ to .gitignore to prevent session ID leaks

Codex consult mode stores session IDs in .context/codex-session-id.
Without this ignore rule, session IDs could leak into commits.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -3,6 +3,7 @@ node_modules/
 browse/dist/
 .gstack/
 .claude/skills/
+.context/
 /tmp/
 *.log
 bun.lock