docs(claude-md): strengthen testing requirements and add UI test command

[J2TeamNNL]

Summary

• Updates principle [WIP] Fix tab state persistence and query execution timing issues TableProApp/TablePro#7 (Testability) to require unit tests for all testable code changes and UI automation for user-flow changes when deterministic
• Adds xcodebuild ... -only-testing:TableProUITests command to the Build & Development Commands section
• Updates mandatory rule Fix data grid undo/redo and multi-row deletion bugs TableProApp/TablePro#4 (Tests) with the same stricter wording

These are project-convention changes that affect every future PR, separated from the feature work in TableProApp#1422.

https://claude.ai/code/session_018hni1aSrv94iwgKb1SvApq

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[J2TeamNNL]

Tạo nhầm repo. PR đúng: TableProApp#1465