fix(ios): preserve code block styles inside list items

[Mile-Away]

Summary

When a fenced code block appears inside a list item (e.g. ```text inside an ordered list), ListItemRenderer's paragraph style enumeration overwrites the code block's own styles with list item styles. This causes:

• List markers (e.g. "2.") appearing on every line inside the code block
• Code block padding and LTR indentation being replaced by list indentation

Root cause: ListItemRenderer.m enumerates ListDepthAttribute over the entire item range and applies list paragraph styles to all segments that don't belong to a nested sub-list. Code block ranges (which have CodeBlockAttributeName set by CodeBlockRenderer) were not excluded.

Fix: Check for CodeBlockAttributeName in the enumeration callback and skip those ranges, preserving the paragraph style already applied by CodeBlockRenderer.

Reproduction

1. First item
2. Second item:

\`\`\`text
Line A
Line B
Line C
\`\`\`

3. Third item

Before this fix, lines inside the code block render with "2." list markers on iOS.

Test plan

• Verify fenced code blocks inside ordered/unordered list items render without list markers
• Verify code block background, padding, and LTR alignment are preserved
• Verify nested lists still render correctly (no regression)
• Verify task list items with code blocks render correctly

🤖 Generated with Claude Code

[hryhoriiK97]

@Mile-Away thank you for the PR with fix! One thing which should be covered - he same pattern exists in applyCheckedDecorationsTo:range:nestingLevel.

Please add the same guard there as well:

  [output enumerateAttribute:ListDepthAttribute
                     inRange:range
                     options:0
                  usingBlock:^(NSNumber *depth, NSRange segmentRange, BOOL *stop) {
                    BOOL isNestedSubItem = (depth && [depth integerValue] > nestingLevel);
                    if (isNestedSubItem) {
                      return;
                    }

                    NSNumber *isCodeBlock = [output attribute:CodeBlockAttributeName
                                                     atIndex:segmentRange.location
                                              effectiveRange:nil];
                    if ([isCodeBlock boolValue]) {
                      return;
                    }

                    [output addAttributes:checkedAttrs range:segmentRange];
                  }];