[Feature]: Allow viewing agent- and level-specific logs from the management console

## Summary

Improve the logging system so that users can view logs of each agent at different log levels directly from the management console.

## Component(s) Affected

- [x] Core / Backend (app, agents, config, providers, utils, local_models)
- [x] Console (frontend web UI)

## Problem / Motivation

It is currently inconvenient for users and administrators to monitor, debug, or troubleshoot issues with different AI agents, as the logs are not easily accessible or filterable in the management console. Better logging observability would significantly enhance operational experience and speed up issue resolution, especially for enterprise-scale deployments.

## Proposed Solution

- Add the ability to filter and view logs of individual agents directly in the management console.
- Allow filtering logs by log levels (INFO, WARNING, ERROR, etc.).
- Enable searching, filtering, and analyzing logs within the console UI.
- Consider using structured/log-friendly formats and possible integrations with third-party log analysis platforms.

## Alternatives Considered

- Download logs for offline analysis (less user-friendly).
- Remote logging to external platforms only.

## Additional Context

This feature will enhance the system's maintainability, monitoring, and debugging, making it friendlier for users and enterprise operations.

## Willing to Contribute

- [ ] I am willing to open a PR for this feature (after discussion).