feat(boundaries): WP-03 — contracts purity + ApiClient confinement

Lint-enforce two architecture rules that were only documented (ADR-0001),
landing the rules with the fixes so the build stays green:

- contracts/ imports nothing: dashboard-view.dto.ts is now pure wire shapes
  (inline string-union enums, no domain imports). The DashboardView FE-view
  type moves to the adapter, which maps wire → domain (compiler-enforced seam).
- ApiClient lives only in infrastructure: change-request-form (UI) no longer
  injects ApiClient — a new ChangeRequestAdapter owns the client and the submit
  becomes a createSubmitChangeRequest() command factory (createDraftSync shape).
  draft-sync's wire-DTO import becomes type-only (allowed via allowTypeImports).
- Role type moves to shared/domain/role.ts; the ?role= reader stays in
  shared/infrastructure/role.ts.
- eslint: contracts import-ban + @typescript-eslint/no-restricted-imports on
  api-client (value-only; type imports permitted; infra + shared/upload exempt).

Also fixes a PRE-EXISTING bug found while verifying the flow: change-request-form
never imported FormsModule, so (ngSubmit) didn't bind and the submit button did a
native form submit (page reload) instead of submitting. Verified end-to-end in the
running app: submit → command → adapter → backend → reference, success alert shown.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/shared/domain/role.ts

@@ -0,0 +1,7 @@
+/**
+ * The two-person letter workflow's role: who is acting, a drafter or an approver.
+ * A pure domain type (no framework, no reading mechanism) — the `?role=` reader and
+ * the X-Role header live in shared/infrastructure/role.ts. Consumers (brief.store,
+ * letter-composer) depend on this type, not on how the role is obtained.
+ */
+export type Role = 'drafter' | 'approver';

src/app/shared/infrastructure/role.ts

@@ -1,12 +1,13 @@
-/**
- * Dev-only role stand-in. This POC has one faked self-service user and no real
- * identities, so the two-person letter workflow (drafter vs approver) is driven by
- * a `?role=` query param — exactly the pattern of the `?scenario=` toggle. The
- * backend receives it as an `X-Role` header (see role.interceptor) and enforces the
- * approver≠drafter rule; the FE derives `editable` from it.
- */
-export type Role = 'drafter' | 'approver';
+import { Role } from '@shared/domain/role';
 
+/**
+ * Dev-only role stand-in (the reading MECHANISM; the `Role` type is domain). This
+ * POC has one faked self-service user and no real identities, so the two-person
+ * letter workflow (drafter vs approver) is driven by a `?role=` query param —
+ * exactly the pattern of the `?scenario=` toggle. The backend receives it as an
+ * `X-Role` header (see role.interceptor) and enforces the approver≠drafter rule;
+ * the FE derives `editable` from it.
+ */
 export function currentRole(): Role {
   return new URLSearchParams(window.location.search).get('role') === 'approver' ? 'approver' : 'drafter';
 }