feat(skatteverket): expose filed VAT declarations and decisions via the v1 API (#1773)

* feat(skatteverket): expose filed VAT declarations and decisions via the v1 API

Add GET /api/v1/companies/:companyId/skatteverket/vat-declarations, returning
a period's momsdeklaration as Skatteverket has it on file: the submitted
declaration (SKV /inlamnat) and Skatteverket's beslut (SKV /beslutat), either
individually via ?state= or both.

- Auth: compliance:read scope; member-visibility read model per #1673
  (resolveReadAuth: caller's token, any member's active token, or system
  credentials with a verified ombud grant).
- Architecture: core reaches the Skatteverket extension through the
  registry-resolved services channel (contract in
  lib/skatteverket/declaration-status.ts), so core never imports from
  @/extensions/.
- New structured error SKATTEVERKET_API_ERROR (502) for upstream SKV
  failures; 404 from SKV maps to submitted/decided = null with HTTP 200.
- 19 new tests (route: auth, validation, extension-disabled, happy path;
  extension service: auth resolution, state filtering, SKV error mapping).

Fixes #1663

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(skatteverket): address review findings on the vat-declarations read API

Consolidated fixes for PR #1773 review round:

- apiskill sync (core-build Checks): map the new skatteverket endpoint
  group into the periods.md reference and regenerate skills/accounted-api
  (124 -> 125 operations).
- CodeRabbit: parse the SKV 2xx body before writing the audit row, so an
  unreadable body is audited as skv_error and returns the structured
  SKATTEVERKET_API_ERROR 502 instead of escaping as an internal 500;
  regression test added.
- Compliance swarm (ISO A.8.12 / SOC2 CC6.1): stop forwarding the raw
  upstream SKV response body to API consumers; the caller now gets the
  status code and a generic Swedish message, the body is logged
  server-side only.
- Compliance swarm (GDPR Art.30): add the moms.declaration_status_read
  processing activity to .compliance/ropa.yaml (live read, no payload
  persisted, audit-log metadata only).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

lib/errors/structured-errors.ts

@@ -3342,6 +3342,11 @@ const SKATTEVERKET: Record<string, StructuredErrorEntry> = {
     message_en: 'Skatteverket rate limit exceeded.',
     retryable: true,
   },
+  SKATTEVERKET_API_ERROR: {
+    httpStatus: 502,
+    message_sv: 'Skatteverkets tjänst svarade med ett fel. Se detaljerna och försök igen.',
+    message_en: 'The Skatteverket API returned an error. See details for the upstream message.',
+  },
 }
 
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