feat(invoices): disclose invoice-register coverage gaps + net-amount search (#2122)

* feat(invoices): disclose invoice-register coverage gaps + amount search

After a SIE migration or verifikat backfill, customer invoices exist only
as journal entries: the invoice list, kundreskontran, /api/invoices, v1
invoices.list, and MCP list_invoices all looked complete while silently
omitting everything before the register's first invoice (user report:
two invoiced fees nearly re-invoiced as "uninvoiced").

- lib/invoices/invoice-register-coverage.ts: coverage boundary = earliest
  register invoice; flags posted non-invoice-engine AR verifikat
  (1510/1513) before it. AR-keyed, not source_type='import'-keyed, so
  manual/API backfills are caught too.
- Invoice list page: one attn line disclosing the boundary (sv+en).
- Kundreskontra: register_coverage in the report payload, rendered in the
  summary card and as an explanation under "Ej avstamd".
- /api/invoices GET: invoice_register_coverage in the response.
- v1 invoices.list: meta.coverage + registry pitfall documenting it.
- MCP gnubok_list_invoices: invoice_register_coverage + coverage_note on
  the first page, pointing agents at gnubok_query_journal.
- Search: lib/invoices/invoice-search.ts matches net (subtotal) and gross
  amounts with sv-SE formatting, alongside number/customer matching; a
  known net amount like 14 000 now finds the 17 500 kr row.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VcW5BU6mU1vNbWpkMKHbHF

* fix(invoices): harden register-coverage probe, period-gate reconciliation note, regen api skill

Skeptic + CI findings folded into one pass:

- Coverage probe: a failed AR lookup now degrades to UNKNOWN
  (NO_INVOICE_REGISTER_COVERAGE), never to a confident "complete".
- Probe driven from journal_entries (company-indexed) with the AR line
  condition as an inner embed, instead of the lines-table-with-embed-filters
  shape that lateral-scans every tenant (lib/bookkeeping/entry-lines.ts).
- DEBIT-only 1510/1513 lines; excludes every invoice-engine source type
  (invoice_created, invoice_paid, invoice_cash_payment, credit_note,
  reminder_fee, rot_rut_payout, storno, correction): an advance payment
  crediting 1510 or a re-dated rattelse of an engine entry no longer flags.
- covers_from ignores drafts so a backdated draft cannot move the boundary.
- Kundreskontra "Ej avstamd" explanation is now gated on pre-register AR
  debits existing IN the reconciled period (new
  ARReconciliationResult.pre_register_ar_in_period): prior-period migration
  history cannot explain this period's difference and must not excuse a
  real felbokning. Wording no longer says "snarare an felbokning".
- MCP coverage_note states the earliest register invoice date rather than
  claiming the register "covers" from it.
- Amount search compares magnitudes so credit notes (negative totals) are
  findable; "-17500" parses; null amounts never match "0".
- skills/accounted-api regenerated from the registry (apiskill:check).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VcW5BU6mU1vNbWpkMKHbHF

* chore(api-skill): regenerate accounted-api skill after merging origin/main

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VcW5BU6mU1vNbWpkMKHbHF

* fix(invoices): round-2 review fixes for register-coverage disclosure

- covers_from now anchors on real invoices only (document_type='invoice',
  non-draft): proformas/delivery notes cannot move the boundary.
- INVOICE_ENGINE_SOURCE_TYPES exported + a test scans the engine writers
  (invoice-entries, reminder-fee, rot-rut, storno-service) so a future
  source_type cannot silently become false pre-register evidence.
- Kundreskontra guidance names both 1510 and 1513.
- MCP gnubok_list_invoices outputSchema declares invoice_register_coverage
  and coverage_note.
- v1 reports.ar-ledger documents data.register_coverage; invoices.list
  example made internally consistent; api skill regenerated.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VcW5BU6mU1vNbWpkMKHbHF

* fix(mcp): keep gnubok_list_invoices outputSchema minimal to hold the tools/list token budget

The expanded schema from the round-2 review pushed tools/list to 61 726
tokens against the held 61 600 ceiling (payload-size.bench.test.ts). The
ceiling is policy, not a baseline to bump: the description already tells
agents to read invoice_register_coverage/coverage_note, and paginatedSchema
has no additionalProperties:false, so the fields stay schema-valid.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VcW5BU6mU1vNbWpkMKHbHF

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>

components/reports/views/index.tsx

@@ -3107,6 +3107,10 @@ interface ARLedgerData {
     total_overdue: number
     unpaid_count: number
     unconverted_fx_count: number
+    register_coverage?: {
+      covers_from: string | null
+      has_pre_register_invoices: boolean
+    }
   }
   reconciliation: {
     ar_ledger_total: number
@@ -3114,6 +3118,7 @@ interface ARLedgerData {
     difference: number
     is_reconciled: boolean
     unconverted_fx_count: number
+    pre_register_ar_in_period?: boolean
   } | null
 }
 
@@ -3297,6 +3302,11 @@ export function ARLedgerView({ periodId }: { periodId: string }) {
                 {ledger.unconverted_fx_count} faktura i utländsk valuta utan växelkurs är inte med i totalen.
               </p>
             )}
+            {ledger.register_coverage?.has_pre_register_invoices && ledger.register_coverage.covers_from && (
+              <p className="mt-1 text-xs text-muted-foreground">
+                Fakturor före {formatDate(ledger.register_coverage.covers_from)} kan ligga som bokförda verifikat och ingår inte i reskontran.
+              </p>
+            )}
           </CardContent>
         </Card>
         <Card>
@@ -3421,6 +3431,17 @@ export function ARLedgerView({ periodId }: { periodId: string }) {
                     {reconciliation.unconverted_fx_count} kundfaktura i utländsk valuta saknar växelkurs: differensen kan bero på saknade kursuppgifter snarare än felbokning.
                   </p>
                 )}
+                {/* Only when pre-register AR debits exist IN the reconciled
+                    period: prior-period migration history contributes nothing
+                    to this period's balance, and offering it as an explanation
+                    there would cushion a genuine felbokning. */}
+                {!reconciliation.is_reconciled &&
+                  reconciliation.pre_register_ar_in_period &&
+                  ledger.register_coverage?.covers_from && (
+                    <p className="text-xs text-muted-foreground">
+                      Perioden innehåller verifikat med kundfordringar före {formatDate(ledger.register_coverage.covers_from)} som inte ligger i fakturaregistret (t.ex. efter en migrering): differensen kan bero på det. Kontrollera huvudboken på <AccountNumber number="1510" /> och <AccountNumber number="1513" /> innan du letar felbokning.
+                    </p>
+                  )}
               </div>
             </div>
           </CardContent>