feat: add list.markerMinWidth to align UL/OL/task lists

[mozharovsky]

What/Why?

Today each list kind reserves its own natural marker column width: bulletSize / 2 for unordered, the width of "99." at the marker font for ordered, and the checkbox size for tasks. Mixed content therefore looks ragged — bulleted rows sit far to the left of numbered rows, task rows to the left of both.

This PR adds one optional style, list.markerWidth, that acts as a minimum reserved marker column width applied to all three list kinds. Each list's effective column becomes max(markerWidth, natural), so consumers can line up mixed lists without shrinking ordered lists or resizing the bullet/checkbox glyphs. Values below the natural width are ignored; leaving it unset preserves existing behavior.

<EnrichedMarkdownText
  markdownStyle={{
    list: {
      bulletSize: 6,
      markerWidth: 20, // widens UL and task rows to line up with OL at 16pt
    },
  }}
  ...
/>

Implementation

• Public API: ListStyle.markerWidth?: number (type-only; JSDoc on the internal type captures the sentinel contract).
• Internal codegen prop: concrete Float; negative = auto. Default is set in normalizeMarkdownStyle so consumers never touch the sentinel.
• iOS: StyleConfig gets a new ivar + getter/setter; effectiveListMarginLeftForBullet / effectiveListMarginLeftForNumber floor by markerWidth; new effectiveListMarginLeftForTask handles task rows. Wired through StylePropsUtils and included in MeasurementCache so cached sizes invalidate when the prop changes. ListItemRenderer.m routes the task case through the new accessor.
• Android: ListStyle carries the field and exposes effectiveMarkerWidth(natural). UnorderedListSpan, OrderedListSpan, and TaskListSpan all apply the floor. Bullets and checkboxes now position themselves relative to the reserved column's right edge (matching iOS), which stays pixel-identical when the column width equals the natural glyph width.
• Docs: new row in docs/STYLES.md.
• Example app: apps/example/src/markdownStyles.ts sets markerWidth: 20 so the feature is visible against the existing mixed-list sample content.

Testing

• iOS example app built and launched on iPhone 17 Pro simulator.
• Android example app built and launched on Pixel 3a (API 34) emulator.
• Verified before/after visually on the existing sampleMarkdown which has mixed UL, OL, and task lists on both platforms.
• Behavior unchanged when markerWidth is undefined (floor is below natural).

Screenshots

Same mixed-list sample content (UL + OL + task rows from sampleMarkdown.ts) rendered with and without markerWidth: 20.

iOS (iPhone 17 Pro simulator)

Default	markerWidth: 20

Android (Pixel 3a API 34 emulator)

Default	markerWidth: 20

PR Checklist

• Code compiles and runs on iOS
• Code compiles and runs on Android
• Updated documentation/README if applicable
• Ran example app to verify changes

[hryhoriiK97]

@mozharovsky, thank you for the PR! It's a great improvement for the lists 💪 I've left a few comments. 🙂

[mozharovsky]

Thanks for the thorough review, @hryhoriiK97 — all seven points accepted in d505e61. Summary:

• Rename list.markerWidth → list.markerMinWidth across public/internal types, codegen specs, iOS ivar + getter/setter, Android field, style normalizer (native + web), docs, and the example.
• Default is now 0 instead of a -1 sentinel. Floor semantics (max(0, natural) === natural) made the sentinel unnecessary; the three < 0 guards are gone.
• iOS effectiveListMarginLeftForBullet / …ForNumber / …ForTask are now single-line MAX(...) calls — no helper needed.
• Android effectiveMarkerWidth uses idiomatic coerceAtLeast; fromReadableMap parsing is one line; KDoc dropped (the name speaks for itself).
• JSDoc moved onto the public MarkdownStyle.ListStyle field (where consumers hover it); dropped from MarkdownStyleInternal.

Net diff from this commit: -48 / +30. Ready for another look whenever you have a minute.

[hryhoriiK97]

LGTM! Thank you for the contribution. @mozharovsky, markerMinWidth will be included in tomorrow’s nightly release.