Added

• Task revision field and updatedAt timestamp for optimistic locking. Every write increments revision; expected_revision param on update_task, claim_task MCP tools and API routes rejects stale updates with REVISION_CONFLICT (409).
• readTask(id) delegate method on DirectoryMarkdownParser for single-task lookups without reading all tasks.
• Task claim tracking: claimedBy (person ID) and claimedAt (ISO timestamp) fields on TaskConfig, set automatically by claim_task and exposed on update_task MCP tool and API route.
• Person agent status fields: status (idle/working/offline), lastSeen (ISO timestamp), currentTaskId for orchestrator tracking. Exposed on update_person MCP tool.
• Claim guard on update_task: when agent_id is provided, In Progress tasks claimed by a different agent are rejected with CLAIM_GUARD (409). Owner (human) can always override by omitting agent_id.