Preserve style-only footer child alignment

## Problem
The style-only footer shell is preserved, but Home footer child alignment still drifts: the Pathway brand renders left-aligned instead of centered.

## Direction
Preserve authored alignment for meaningful children retained within style-only visual shells through generic presentation projection.

## Acceptance
- Home footer brand x position matches source.
- Footer shell geometry remains exact.
- Other style-only shells do not regress.
- Transformer contracts and parity fixtures pass.

## AI assistance
OpenAI gpt-5.6-sol through OpenCode analyzed the parity evidence and drafted this issue. Chris Huber remains responsible for scope and implementation decisions.

Start with the generic presentation projection, transformer contracts, and parity fixtures mentioned in the issue. Compare the Home footer brand x position with the source while checking that footer shell geometry stays exact; done means the alignment matches and other style-only shells show no regressions with all contracts and fixtures passing.

Written by the indexing model from the issue text.