docs: Update v1.1.0 documentation for EventType enum, heartbeat tracking, task querying, and architectural refinements

[youf3]

Summary

• EventType enum — documents the new EventType string enum in quantnet_mq, listing all typed constants (agentState, experimentResult, agentHeartbeat, agentTaskSchedulerPhase, agentTaskSchedulerTask, agentTaskResult) and links them to their corresponding MonitorEvent fields.
• Agent heartbeat tracking — documents the 60-second staleness threshold; the monitor plugin now uses agentHeartbeat events to maintain a per-node last-seen timestamp, and the controller excludes stale agents from experiment path matching.
• getTasks RPC — documents the new monitor plugin RPC command for querying recorded agent task results, including optional agent filtering and the fields returned per entry.
• Configuration refactoring — documents the new -c/--config CLI flag for both the controller and agent, updated config file search paths (removing the previously probed $VIRTUAL_ENV path), and explicit error-on-missing-file behavior.
• Topology API — documents the full parameter on the getInfo topology RPC, which returns complete node/channel data and aggregate counts when enabled.
• Routing fixes — documents MultiGraph support and quantum link recovery fallback behavior.
• Scheduling — documents controller-side separation of experiment vs. calibration request paths and per-agent error reporting.
• MongoDB config — adds mongo_host and mongo_port config reference entries.
• Changelog — fills in the 1.1.0 changelog entries for qn-mq, qn-server, and qn-agent.