feat: add official Codex skill and harden task execution

Install and update artemis-use with task diagnostics and plugin guidance. Preserve cross-device file receipts, review canonical reports, guard stage transitions and reduce small history summaries. Improve exploration lifecycle, request recovery and browser live connections.

tests/unit/agents/test_operator_transcript.py

@@ -54,8 +54,8 @@ from artemis.memory.transcript import (
 
 # SHA-256 snapshots of the legacy system message with the fixed inputs below.
 # Update these when an intentional template change alters the rendered prompt.
-GOLDEN_EMPTY_PLAN = "58bf034527b2d782f7746d8e379cb0decc44a05dfa18cb73153d49cd8265002b"
-GOLDEN_SENTINEL_PLAN = "b328052390a0a815c096b8ec4c5286421be487e7b6cd3bec55d6bc62a1f2518f"
+GOLDEN_EMPTY_PLAN = "e83c2c6cc1e28b04898e6602194cb2fbac67fe5a3aec8e109872c375f4e59944"
+GOLDEN_SENTINEL_PLAN = "dba4eb2cdcd9389148ac3228c6e9e69fdbe8d407dec76b58aa65509ad768c392"
 
 SCREENSHOT_B64 = base64.b64encode(b"fake-jpeg-bytes").decode("utf-8")