fix(agent-manager): parse current Codex session messages

[codeaholicguy]

Summary

• Parse current Codex response_item message records in agent detail conversations.
• Parse completed AgentMessage event records from current Codex JSONL logs as fallback.
• Deduplicate mirrored current Codex response_item / event_msg records in agent detail, preferring canonical response_item messages.
• Use normalized current-schema parsing for agent list summaries and status classification.
• Keep legacy payload.message parsing intact.

Validation

• npm run test -- CodexAdapter.test.ts from packages/agent-manager: 66 passed.
• Regression checks: new parser tests failed with corresponding production parser changes temporarily reverted, then passed after restore.
• npm run typecheck from packages/agent-manager: passed.
• npm run lint from packages/agent-manager: passed.
• npm run test from packages/agent-manager with process access: 502 passed.
• Commit hooks ran repo-wide nx run-many -t lint and nx run-many -t test: passed.

Risks

• Low. Event-message fallback remains for logs without response_item; mirrored records with a matching turn/role/content are skipped to avoid duplicate detail output.