Fix browser crash when @Highlight value is empty string

[michaelomichael]

Having a field/parameter annotated with @Highlight can cause the browser tab to crash when the value of that field/parameter is an empty string ("").

This is because the generated "highlight" regex pattern will match every single text node due to it matching on the empty string.

This fix ignores any zero-length "highlight" values.

[paul-brooks]

Good find, the diagnosis is spot on: an empty highlight builds a regex that matches every text node and hangs the tab.

One wrinkle. buildHighlightRegex has two other callers, DataTable.tsx:21 and FixturesTable.tsx:20, so the RegExp | null return breaks tsc, and at runtime they guard on highlights.length === 0, which doesn't catch [""]. They'd get null and text.split(null) coerces to the string "null", so that word vanishes and the following text gets highlighted instead.

You're busy, so I've pushed a commit rather than bounce it back. It returns /(?!)/g instead of null when nothing survives the filter, which never matches, so split returns the whole string and test is false. Same fix, no caller changes, no null to thread through. Added tests too since there was no coverage for this.

CI was green on your original despite tsc failing, because :ui:viteBuild shells straight to vite build and skips the type check. Raised separately as #187.

Thanks for both of these.

[michaelomichael]

Looks good.