[lexical] Bug Fix: Update selection format and style on programmatic select

[1012ayush]

Description

What is the current behavior that you are modifying?
When moving a selection programmatically (e.g., using $getRoot().selectStart()), the RangeSelection object updates its anchor and focus properties to the new location, but it fails to update the format and style caches. This results in the new selection holding stale formatting data from the previous cursor position.

What are the behavior or changes that are being added by this PR?
This PR ensures that programmatic selection updates correctly synchronize the format and style caches:

1. In LexicalElementNode.ts, the select() method's fallback logic now resets selection.format = 0 and selection.style = '' to clear stale data when a new element is selected.
2. In LexicalTextNode.ts, the select() method now explicitly inherits the target node's formatting by setting selection.format = this.getFormat() and selection.style = this.getStyle().

Closes #8817

Test plan

Before

When selecting text with a specific format (e.g., bold) and then triggering a programmatic selection change (like clicking a button that calls selectStart()), $getSelection().hasFormat('bold') incorrectly remains true because the bitmask is never cleared.

After

Programmatic selection changes now correctly flush the format cache. Moving the selection via selectStart() to an unformatted node correctly returns false for $getSelection().hasFormat('bold').

Note: Verified locally using the reproduction StackBlitz provided in the original issue.

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Project	Deployment	Actions	Updated (UTC)
lexical	Ready	Preview	Jul 9, 2026 4:28am
lexical-playground	Ready	Preview	Jul 9, 2026 4:28am

[etrepum]

This approach fails existing tests and doesn't add any new tests