[chubes4]

Summary

Repeating background-only layers now stay backgrounds instead of becoming intrinsic-size images. WordPress receives explicit auto sizing when no size was authored, preserving the tile rather than stretching it.

What changed

• Reuse CoverStyleResolver repetition detection and preserve resolved URL, repeat, size, position, and presentation attributes.
• Replace the empty wrapper with the background group instead of nesting it.
• Add regression coverage for default and authored sizes, shorthand repetition, and the non-repeating cover image path.
• Rendered before/after evidence using WordPress and Chrome: before, one 40×40 image; after, intrinsic 40px tiles repeat across an 800×206 box. Heading line-height was pinned to reproduce the reported box height; screenshot pixels confirmed repetition.

Verification

• passed on 16634ab. Base trunk@d1e6b64 unchanged.

set -e
cd php-transformer
(test -d vendor || composer install --no-progress --no-interaction)
( while sleep 60; do echo "gate heartbeat: composer test still running"; done ) &
hb=$!
trap 'kill $hb 2>/dev/null || true' EXIT
composer test

• CI: pending

Cook run

• Gate 1: tree f6b70d4ec965396a0b5efd7602fab5a865d9eab9, fingerprint d4b87f8cd818afa7699db6848eaa92b0b6db71847a5b54891c8bc555c6f19d46

AI assistance

Tool: Homeboy (pi) · Model: gpt-6.1-sol (tier roadie/cook-heavy) · Used for: AI implemented the transformer changes, added regression coverage, and verified suite and rendered behavior.

Closes #3552