Fiscal period and multi bank (#228)

* feat: add fiscal period backward chaining and entry date validation

Support creating fiscal periods before the earliest existing period
(backward chaining) for backfill scenarios, alongside the existing
forward chaining. The engine now validates that entry dates fall within
the selected fiscal period, with a Swedish error message. The journal
entry form auto-selects the matching period and shows a warning with
a CreatePeriodDialog when no period covers the entry date.


* feat: support multi-bank-account for imports and reconciliation

Plumb a configurable settlement account through the entire bank import
pipeline — mapping engine, transaction entries, ingest, and
reconciliation — so secondary bank accounts (e.g. 1931, 1932) work
correctly instead of hardcoding 1930. Adds a get_unlinked_bank_lines
RPC that generalizes the existing get_unlinked_1930_lines with a
fallback for backwards compatibility. The bank file import UI now shows
a bank account selector when multiple 19xx accounts exist. Also adds
default_vat_code/sru_code to account creation and fixes uploadDocument
argument order in enable-banking sync.

lib/bookkeeping/mapping-engine.ts

@@ -50,8 +50,11 @@ export async function evaluateMappingRules(
   supabase: SupabaseClient,
   companyId: string,
   transaction: Transaction,
-  entityType?: EntityType
+  entityType?: EntityType,
+  settlementAccount?: string
 ): Promise<MappingResult> {
+  const bankAccount = settlementAccount || '1930'
+
   // Fetch all active rules (user-specific + system defaults), ordered by priority
   const { data: rules, error } = await supabase
     .from('mapping_rules')
@@ -63,29 +66,29 @@ export async function evaluateMappingRules(
   if (error || !rules || rules.length === 0) {
     // Try counterparty templates before static template fallback
     const counterpartyResult = await evaluateCounterpartyTemplates(supabase, companyId, transaction, entityType)
-    if (counterpartyResult) return counterpartyResult
+    if (counterpartyResult) return applySettlementAccount(counterpartyResult, bankAccount)
 
     const templateResult = evaluateTemplateRules(transaction, entityType)
-    if (templateResult) return templateResult
-    return getDefaultResult(transaction)
+    if (templateResult) return applySettlementAccount(templateResult, bankAccount)
+    return getDefaultResult(transaction, bankAccount)
   }
 
   // Evaluate each rule in priority order
   for (const rule of rules as MappingRule[]) {
     if (matchesRule(rule, transaction)) {
-      return buildResult(rule, transaction, entityType)
+      return applySettlementAccount(buildResult(rule, transaction, entityType), bankAccount)
     }
   }
 
   // Try counterparty templates before static template fallback
   const counterpartyResult = await evaluateCounterpartyTemplates(supabase, companyId, transaction, entityType)
-  if (counterpartyResult) return counterpartyResult
+  if (counterpartyResult) return applySettlementAccount(counterpartyResult, bankAccount)
 
   // Try template-based matching before default fallback
   const templateResult = evaluateTemplateRules(transaction, entityType)
-  if (templateResult) return templateResult
+  if (templateResult) return applySettlementAccount(templateResult, bankAccount)
 
-  return getDefaultResult(transaction)
+  return getDefaultResult(transaction, bankAccount)
 }
 
 /**
@@ -261,13 +264,13 @@ function buildResult(rule: MappingRule, transaction: Transaction, entityType?: E
 /**
  * Default result when no rule matches (uncategorized)
  */
-function getDefaultResult(transaction: Transaction): MappingResult {
+function getDefaultResult(transaction: Transaction, bankAccount = '1930'): MappingResult {
   const isExpense = transaction.amount < 0
 
   return {
     rule: null,
-    debit_account: isExpense ? '6991' : '1930',
-    credit_account: isExpense ? '1930' : '3900',
+    debit_account: isExpense ? '6991' : bankAccount,
+    credit_account: isExpense ? bankAccount : '3900',
     risk_level: 'MEDIUM',
     confidence: 0.1,
     requires_review: true,
@@ -277,6 +280,20 @@ function getDefaultResult(transaction: Transaction): MappingResult {
   }
 }
 
+/**
+ * Replace any default 1930 references in a mapping result with the actual settlement account.
+ * This allows mapping rules and templates that don't explicitly set a bank account
+ * to work correctly with secondary bank accounts (e.g. 1931).
+ */
+function applySettlementAccount(result: MappingResult, bankAccount: string): MappingResult {
+  if (bankAccount === '1930') return result
+  return {
+    ...result,
+    debit_account: result.debit_account === '1930' ? bankAccount : result.debit_account,
+    credit_account: result.credit_account === '1930' ? bankAccount : result.credit_account,
+  }
+}
+
 /**
  * Save a user-level mapping rule learned from categorization.
  *