fix(bookkeeping): allow EF förlängt räkenskapsår on first-period edit + hide Recapt widget (#481)

* fix(bookkeeping): allow EF förlängt räkenskapsår on first-period edit + hide Recapt widget

PATCH /api/bookkeeping/fiscal-periods/[id] rejected enskild firma first
fiscal periods extended into the next calendar year (e.g. 2020-10-04 →
2021-12-31, 15 mån) even though BFL 3 kap. permits up to 18 months when
the EF starts after 1 juli. Validator and DB trigger already supported
this; only the API check ignored isFirstPeriod. Move the isFirstPeriod
calculation above the EF rule and split it into "end must be 31 dec
(always)" + "start must be 1 jan (only when not first period)". Brings
the API into agreement with the frontend's validateFirstPeriod logic.

Also mount RecaptHideWidget in the root layout, which calls
window.recapt('feedback', { widget: 'hide' }) once the SDK is ready.
The floating bubble no longer appears in the bottom-right; Recapt's
identify and programmatic feedback APIs continue to work unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(bookkeeping): address PR-481 review — standard guards, shared helpers, 18-month cap regression

- Use shared createMockRequest / createMockRouteParams from tests/helpers.ts
- Add 401 (unauthenticated), 400 (malformed body), 404 (unknown period)
- Rename "mid-month startdatum" case to "not 1 januari" (request sends 2026-02-01, a month boundary, not mid-month — the rule rejects any non-Jan-1)
- Add defense-in-depth case proving validatePeriodDuration rejects a 24-month EF first period (BFL 3 kap. 18-month cap), since the new EF end-date guard runs before duration validation

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* test(bookkeeping): lock in EF subsequent-period end-date guard

The start-must-be-1-jan + end-must-be-31-dec guards together force EF
subsequent periods to a 12-month span. validatePeriodDuration's 18-month
universal cap doesn't enforce this on its own — only the route's per-EF
guards do. Add a regression test so a future refactor of the EF block
can't silently allow a 13-month subsequent period (e.g. 2026-01-01 →
2027-01-31), addressing PR-481 swedish-compliance review finding #1.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

components/RecaptHideWidget.tsx

@@ -0,0 +1,38 @@
+'use client'
+
+import { useEffect } from 'react'
+
+/**
+ * Hides Recapt's floating feedback bubble while keeping the SDK active so
+ * `window.recapt('identify', ...)` and programmatic `window.recapt('feedback',
+ * { message })` calls continue to work. Mounted globally in the root layout.
+ */
+export function RecaptHideWidget() {
+  useEffect(() => {
+    let attempts = 0
+    const maxAttempts = 50
+
+    const hide = (): boolean => {
+      if (typeof window.recapt !== 'function') return false
+      try {
+        window.recapt('feedback', { widget: 'hide' })
+      } catch {
+        // best-effort
+      }
+      return true
+    }
+
+    if (hide()) return
+
+    const interval = setInterval(() => {
+      attempts++
+      if (hide() || attempts >= maxAttempts) {
+        clearInterval(interval)
+      }
+    }, 100)
+
+    return () => clearInterval(interval)
+  }, [])
+
+  return null
+}