Write Initial State content for php-i-07 / ex-i-07

Write the Initial State content for php-i-07 and ex-i-07 (REST API Design).

The manifest descriptions were updated on 2026-06-11 to include it; the content does not exist.

Why it sits here and not in beginner

IInitialState spans two layers at once — the PHP controller calls provideInitialState() and the JS reads it with loadState(). A beginner has to hold the whole server-to-frontend picture in their head before it makes sense. So the beginner track deliberately uses a plain axios GET on page load: one extra request, but visible in the network tab and reasonable with concepts they already have.

At intermediate the framing is "sometimes you do not need the roundtrip at all", which lands next to the REST API content and lets the reader actually weigh the tradeoff.

Do not "fix" the beginner modules to use Initial State. That is the decision, not an oversight.

Scope

The content for both tracks, mirroring each other.

Part of #16.

Start by reading the manifest descriptions for php-i-07 and ex-i-07 and tracing the mentioned IInitialState flow from provideInitialState() to loadState(). Write matching Initial State content for both tracks, explain the server-to-frontend tradeoff, and preserve the decision to leave the beginner modules using an axios GET on page load.