⚡ Optimize isAnnotationSelected complexity

[esenmx]

💡 What: Optimized isAnnotationSelected(with:) in AnnotationController.swift by replacing a nested search (getAnnotation) with a direct property access on the FlutterAnnotation model.

🎯 Why: The original code had an unintended O(N * S) time complexity per check (where N is the total annotations on the map, and S is the total number of selected annotations). When an annotation changed, checking whether it was selected involved searching through the map view's selected annotations, and for each selected annotation, performing a linear scan over all annotations to look up by ID. This became notably slow as the map populated with more pins.

The change replaces the O(N) lookup per loop with an O(1) casting and string equality check. The new complexity is strictly O(S), scaling based purely on the number of currently selected annotations, removing the impact of total map size.

📊 Measured Improvement:
Since this is an automated agent environment running on Linux without Swift or Xcode tools available natively, I could not generate physical profiling numbers or a Swift benchmark.
However, considering typical map usage scenarios:

• Baseline Complexity: O(N * S) where N is map annotation count, S is selected annotations count.
• New Complexity: O(S).

If the map has 1,000 annotations and 1 is selected, the operation now takes 1 step instead of 1,000 steps—a 1000x theoretical performance boost for this specific operation. This has a cascading impact as isAnnotationSelected is called heavily during UI updates (updateAnnotation(annotation:)).

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PR created automatically by Jules for task 9734804635131331882 started by @esenmx

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