Feature: EnrichedMarkdownTextInput — automatic RTL parity with EnrichedMarkdownText

[salemkode]

Summary

RTL is documented for EnrichedMarkdownText (docs/RTL.md, docs/TEXT.md), but docs/INPUT.md does not mention RTL or writingDirection / dir. Users editing RTL markdown in the rich input may see behavior diverge from the read-only renderer (e.g. list markers, blockquote edge, caret movement, mixed LTR/RTL).

Proposal / desired behavior

• Parity: EnrichedMarkdownTextInput should follow the same automatic / content-driven RTL rules as EnrichedMarkdownText on native (iOS/Android) and any applicable web story.
• API: If needed, expose an explicit prop (e.g. dir / writingDirection) aligned with EnrichedMarkdownText and web dir so hosts can override locale defaults.
• Docs: Add an RTL section to INPUT.md (platform setup, iOS vs Android, known limitations).

Acceptance criteria (suggested)

• Typing and displaying Arabic/Hebrew/Persian (and mixed with LTR) in the input matches reader layout where the feature set overlaps.
• INPUT documentation describes RTL setup and any props.
• Linked from docs/RTL.md if input has extra caveats.