feat: add codex

Author: kasin-it

.env.example

@@ -36,6 +36,14 @@ CLAUDE_MODEL=claude-opus-4-6
 COMMIT_AUTHOR=ai-workflow-blazity
 COMMIT_EMAIL=ai-workflow@blazity.com
 
+# --- OpenAI / Codex (optional; required only for tickets labeled agent:codex) ---
+# Either OPENAI_API_KEY or CODEX_AUTH_JSON is sufficient. Both may be set; Codex prefers OAuth.
+OPENAI_API_KEY=
+# Full JSON contents of ~/.codex/auth.json after running `codex login` locally, on one line.
+CODEX_AUTH_JSON=
+# Default model for Codex phases. Overrides: o3, o4-mini, gpt-5.4.
+CODEX_MODEL=gpt-5.4
+
 # Sandbox
 MAX_CONCURRENT_AGENTS=3
 JOB_TIMEOUT_MS=1800000