[FIX] Increasing Tests Coverage Back to The Threshold

[antonio-amjr]

Description

• Updated unit tests for log_stream_handler.py and logs_http_server.py to reflect the broadcast-pattern refactor (per-client queues replacing the shared log_queue)
• Added missing test coverage for init_tree(), update_tree_node(), _build_tree(), _get_state(), serve_status(), tree snapshot path, keepalive, tree event routing, and all exception handlers
• Restored overall test coverage from 83% back above the required 85% threshold

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[gemini-code-assist]

Code Review

This pull request introduces a comprehensive suite of unit tests for LogStreamHandler and LogsHTTPServer, covering error handling, tree state initialization, node updates, and various log streaming edge cases. The reviewer feedback focuses on enhancing the robustness of these tests by replacing loose assertions (such as assert_called) with precise ones (like assert_called_once_with) and ensuring that synchronization locks are explicitly verified as acquired.