Enhance ThemedTable2 with performance improvements and tests

[ManuelRomeroA]

This pull request focuses on improving the reliability, performance, and test coverage of the ThemedTable2 widget in the layrz_theme Flutter library. The changes address critical issues like column key collisions, update loss during loading, and isolate safety for closures, while also optimizing multi-select and widget update performance. All debug logging has been removed from the core filtering and sorting logic, and comprehensive widget tests have been added.

Bug fixes:

• Fixed column key collision in _itemsStrings by using column index instead of col.hashCode, preventing silent data corruption when columns share the same headerText. [1] [2] [3]
• Fixed silent update loss: updates arriving while loading are now queued via a _pendingUpdate flag and processed after the current operation completes. [1] [2] [3] [4]
• Fixed unsendable closure crash: sort keys are now precomputed on the main thread before compute(), ensuring valueBuilder closures that capture BuildContext or i18n objects never cross the isolate boundary. [1] [2] [3]

Performance improvements:

• Improved multi-select performance by introducing an internal Set<T> mirroring _selectedItems for O(1) contains() lookups, replacing previous O(n) checks. [1] [2] [3] [4] [5]
• Improved didUpdateWidget performance by replacing DeepCollectionEquality (O(n)) with a fast O(1) heuristic using identical and length checks. [1] [2]

Codebase cleanup:

• Removed all debugPrint statements from _filterAndSort and related logic. [1] [2] [3] [4]

Testing and versioning:

• Added comprehensive widget tests for ThemedTable2, including regression coverage for key collision, search, sorting, refresh, and widget update scenarios.
• Bumped version to 7.5.22 in pubspec.yaml and .claude-plugin/plugin.json. [1] [2]

[github-actions]

📋 Changelog Summary

This PR includes the following changes:

✨ Features

• enhance ThemedTable2 with widget tests and performance improvements; remove debug prints (85d103a by Manuel romero)
• add SKILL.md for ThemedTable2 with detailed overview and usage examples (eb68032 by Manuel romero)

🐛 Bug Fixes

• ThemedTable2 prevent unsendable closure crash when sorting i18n columns fix: ThemedTable2 resolve column key collision by using positional index instead of col.hashCode fix: ThemedTable2 queue pending updates instead of silent discard during concurrent sort perf: ThemedTable2 replace O(n) List.contains with internal Set for multiselect lookups perf: ThemedTable2 replace O(n) DeepCollectionEquality with O(1) heuristic in didUpdateWidget (d0dd31f by Manuel romero)

📊 Diff Stats

Metric	Count
📄 Files changed	7
🟢 Insertions	$\color{green}\textsf{+1011}$
🔴 Deletions	$\color{red}\textsf{-74}$

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[github-actions]

📊 Test Coverage Report

🎯 Dart/Flutter

Metric	Value
Coverage	13.6%
Lines covered	10807 / 127
Lines missing	-10680

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