feat(fp): WP-08 — one store idiom + machine naming + TEA MDX

Rename change-request.machine.ts's bare State/Msg to ChangeRequestState/
ChangeRequestMsg (the last machine not context-prefixed), document the
createStore-is-the-idiom + naming convention in CLAUDE.md §3, and add the
Foundations/State Machines (TEA) curriculum page. The wizard pages already
wired createStore (confirmed by reading each and by git log) -- the WP's
"hand-wired signal(model)" premise was stale; recorded as a deviation.

docs/backlog/README.md

@@ -47,7 +47,7 @@ for its existing violations, so every WP ends green.
 | [WP-05](WP-05-parse-boundaries.md)      | Parse-don't-validate closure + MDX                           | 1 · FP/DDD                  | done   |
 | [WP-06](WP-06-typed-async.md)           | Generic async template contexts — kill `$any()`              | 1 · FP/DDD                  | done   |
 | [WP-07](WP-07-brief-idioms.md)          | Brief on the shared idioms + RemoteData MDX                  | 1 · FP/DDD                  | done   |
-| [WP-08](WP-08-store-idiom.md)           | One store idiom + machine naming + TEA MDX                   | 1 · FP/DDD                  | todo   |
+| [WP-08](WP-08-store-idiom.md)           | One store idiom + machine naming + TEA MDX                   | 1 · FP/DDD                  | done   |
 | [WP-09](WP-09-pure-logic.md)            | Pure-logic closure: dates + missing command specs            | 1 · FP/DDD                  | todo   |
 | [WP-10](WP-10-button-fidelity.md)       | CIBG button fidelity                                         | 2 · CIBG                    | todo   |
 | [WP-11](WP-11-markup-fidelity.md)       | CIBG markup fidelity: application-link + absent-class triage | 2 · CIBG                    | done   |