refactor: keep anthropic_content_blocks in-memory only (no state.db column)

Drop the hermes_state.py column + persistence plumbing from the salvaged
interleaved-thinking fix. The ordered-block channel covers the failure
window in-memory (turn replayed within the live conversation loop). A
session reloaded from disk after a crash falls back to reconstruction;
if that replay 400s, the thinking-signature recovery (#43667) strips
reasoning_details and retries — one degraded call in a rare resume path
instead of a schema column. Replaces the DB-roundtrip test with a
fallback-shape test.

run_agent.py

@@ -1597,7 +1597,6 @@ class AIAgent:
                     reasoning=msg.get("reasoning") if role == "assistant" else None,
                     reasoning_content=msg.get("reasoning_content") if role == "assistant" else None,
                     reasoning_details=msg.get("reasoning_details") if role == "assistant" else None,
-                    anthropic_content_blocks=msg.get("anthropic_content_blocks") if role == "assistant" else None,
                     codex_reasoning_items=msg.get("codex_reasoning_items") if role == "assistant" else None,
                     codex_message_items=msg.get("codex_message_items") if role == "assistant" else None,
                 )