Preserve auxiliary phone country-selector presentation in wordpress-site-plan

## Problem

The `wordpress_site_plan` form contract represents the Busy Bears Wix country selector as an auxiliary button plus a `phone` control. It retains enough semantics for SSI to set Jetpack `showCountrySelector`, but does not carry the source selector's visible presentation payload (the generic globe SVG, 24 x 24, before the 16 x 16 chevron).

The Jetpack adapter must not invent that glyph. Its built-in unselected state renders only its chevron, so the rendered selector collapses to 18 x 3.594px instead of the source's 40 x 24px selector. This also shifts the phone input left and prevents visual parity.

## Evidence

- Retained source and public `/contact`: `button[data-hook="country-selector-trigger"]` contains a 24 x 24 inline globe SVG and 16 x 16 chevron; source shell is 294 x 42 at 390px.
- Materialized WordPress `/contact` and `/get-a-quote`: SSI emits `showCountrySelector: "1"`; Jetpack exposes 239 country options per responsive instance, but the unselected trigger contains only its built-in 10 x 6 chevron and measures 18 x 3.594px.
- The source HTML has no selected country/default ISO value to map to Jetpack's flag API.
- SSI's current provider destination map only accepts captured CSS facts. A source SVG/icon payload cannot be represented there without inventing a provider-specific asset.

## Requested contract

Extend the generic form presentation/topology contract so an auxiliary country-selector control can carry a safe, provider-neutral visible presentation payload (including its SVG/icon and intrinsic dimensions), associated with the auxiliary control rather than the telephone value input. SSI can then map that payload to a provider-owned prefix destination through its existing adapter boundary.

This should be generic to composite form controls, not Wix- or Busy Bears-specific. It is adjacent to, but not solved by, the closed safe-inline-SVG conversion issue #53: the SVG is preserved in source HTML but is lost when the HTML form is reduced to the `wordpress_site_plan` form representation.

AI assistance: OpenAI gpt-5.6-terra via OpenCode investigated the source and imported phone controls and drafted this issue under OpenAI gpt-6-astra/OpenCode orchestration. The proposed contract needs implementation and end-to-end validation; no fix is claimed by this issue.

Start by locating the wordpress_site_plan form contract, its auxiliary-control representation, and the SSI-to-Jetpack adapter boundary; inspect how presentation data is currently retained and mapped. Validate the change against the source and materialized contact forms, confirming that the country selector preserves the provider-neutral icon payload and the expected 40 x 24px presentation without changing the phone value input.

Written by the indexing model from the issue text.