test: add rate limiter tests for websocket connections

[adcondev]

🎯 What: Missing tests for the ConfigRateLimiter logic in internal/server/rate_limit.go.
📊 Coverage: The new tests cover:

• Limiter Initialization
• Allowing requests below the threshold
• Blocking requests exceeding the threshold
• Independent state tracking for multiple clients
• Time-based pruning logic (ensuring old entries are dropped)
• Safe concurrent execution
  ✨ Result: Improved test coverage and reliability for rate-limiting websocket changes.

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PR created automatically by Jules for task 4273592875046522757 started by @adcondev

[google-labs-jules]

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[github-actions]

⚡ Benchmark Results

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Codecov Report

✅ All modified and coverable lines are covered by tests.

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