feat: UX improvements — nav, reports tabs, dashboard alerts, transaction hints, settings layout

- Move Reports to Finans nav group and auto-expand Övrigt on its pages
- Make report tabs horizontally scrollable with gradient fade on mobile
- Surface deadlines and alerts above the fold on dashboard
- Add dismissible categorization hint card on transactions page
- Split settings company form into 4 separate Cards for scannability
- Add monthly breakdown report, document upload zone, journal entry attachments
- Add batch category selector, receipt document linking, invoice form improvements

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/api/documents/counts/route.ts

@@ -0,0 +1,55 @@
+import { createClient } from '@/lib/supabase/server'
+import { NextResponse } from 'next/server'
+
+/**
+ * GET /api/documents/counts?journal_entry_ids=id1,id2,...
+ * Returns attachment counts per journal entry ID.
+ * Max 50 IDs per request.
+ */
+export async function GET(request: Request) {
+  const supabase = await createClient()
+
+  const { data: { user } } = await supabase.auth.getUser()
+
+  if (!user) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  const { searchParams } = new URL(request.url)
+  const idsParam = searchParams.get('journal_entry_ids')
+
+  if (!idsParam) {
+    return NextResponse.json({ error: 'journal_entry_ids is required' }, { status: 400 })
+  }
+
+  const ids = idsParam.split(',').filter(Boolean)
+
+  if (ids.length === 0) {
+    return NextResponse.json({ data: {} })
+  }
+
+  if (ids.length > 50) {
+    return NextResponse.json({ error: 'Maximum 50 IDs per request' }, { status: 400 })
+  }
+
+  const { data, error } = await supabase
+    .from('document_attachments')
+    .select('journal_entry_id')
+    .eq('user_id', user.id)
+    .eq('is_current_version', true)
+    .in('journal_entry_id', ids)
+
+  if (error) {
+    return NextResponse.json({ error: error.message }, { status: 500 })
+  }
+
+  // Group and count by journal_entry_id
+  const counts: Record<string, number> = {}
+  for (const row of data || []) {
+    if (row.journal_entry_id) {
+      counts[row.journal_entry_id] = (counts[row.journal_entry_id] || 0) + 1
+    }
+  }
+
+  return NextResponse.json({ data: counts })
+}