* fix(grid): normalize smart quotes in JSON input to prevent parse errors
When manually typing JSON values in the data grid, input methods (especially
Chinese IME and macOS smart punctuation) can automatically convert standard
ASCII quotes to smart quotes (U+201C, U+201D, etc.), causing JSON parse failures.
Changes:
- Remove incorrect logic that tried to parse original value before normalization
- Add hasSmartQuotes() function to detect 7 types of smart quotes:
* Chinese quotes: U+201C, U+201D
* German quotes: U+201E, U+201F
* Smart single quotes: U+2018, U+2019
* Fullwidth quote: U+FF02
- Rewrite normalizeSmartQuotes() using charCodeAt to avoid oxc compiler issues
- Add comprehensive tests for MySQL JSON field quote normalization
All existing tests remain passing.
* fix(grid): preserve valid JSON while normalizing smart quotes
