Normalize createTextNode hook data

[olavoasantos]

Problem

Document.createTextNode() normalized nullish input in the Text node constructor, but passed String(data) to the createText hook. As a result, the local node and the Remote DOM hook described different text for the same operation.

Impact

Minor. Creating a text node with null or undefined stored '' locally while emitting 'null' or 'undefined' to the hook. A remote receiver could therefore render text that did not exist in the worker’s local DOM.

Reproduction

window[HOOKS].createText = (_text, data) => console.log(data);

const text = document.createTextNode(null);

text.data; // ''

Before this change, the hook logged 'null' even though text.data was ''; undefined had the equivalent mismatch. It now receives text.data, so both values are ''. Empty and ordinary strings continue to reach the hook unchanged.

Change

Pass the newly created node’s normalized data property to createText rather than independently coercing the original argument. This makes the hook payload use the same single normalization result as local CharacterData.

Tests

Adds focused hook assertions for null, undefined, '', and an ordinary string. Each test verifies the stored text data, the node passed to the hook, and the hook payload agree.

Stack

• Stack: Independent quick wins (#702), layer 3 of 4
• Base: default-custom-event-detail
• Review after PR Default CustomEvent detail to null when omitted #689.

Validation

Fresh GitHub CI on restacked head e1acf97 passes:

• lint;
• type-check and build;
• unit tests with coverage;
• bundle-size checks;
• Playwright end-to-end tests;
• the classified Web Platform Test suite.