Add bank reconciliation workflow and templates

New capability for importing bank transactions (Schwab JSON), matching
against existing ledger entries, creating missing transactions, and
reconciling balances. Includes two new Grist tables (Reconciliations,
BankRules), two bank-import templates, and reference documentation.

templates/bank-import-expense.json

@@ -0,0 +1,86 @@
+{
+  "_meta": {
+    "name": "Bank Import - Withdrawal/Expense",
+    "description": "Record a withdrawal found in bank statement but missing from the ledger",
+    "scenario": "Unmatched bank withdrawal (ATM, check, ACH debit, owner draw)",
+    "when_to_use": [
+      "ATM withdrawals (owner draws)",
+      "Check payments",
+      "ACH debits",
+      "Any bank debit not yet in the ledger"
+    ],
+    "when_not_to_use": [
+      "Withdrawals already recorded in the ledger",
+      "Bill payments with existing bill records - use pay-existing-bill.json"
+    ]
+  },
+  "_variables": {
+    "date_timestamp": "integer - Unix timestamp for transaction date",
+    "amount": "number - Withdrawal amount (positive, will be credited to Checking)",
+    "offset_account_id": "integer - Account to debit (e.g., 24=Owner's Draws, 30=Bank Fees)",
+    "description": "string - Transaction description",
+    "reference": "string - Bank reference or description from statement",
+    "memo": "string - Additional notes (optional)"
+  },
+  "_sequence": [
+    "1. Create Transaction header (Status='Cleared') -> get txn_id",
+    "2. Create TransactionLines (Dr Offset Account, Cr Checking)",
+    "3. Verify IsBalanced = true"
+  ],
+  "records": {
+    "transaction": {
+      "_doc": "Step 1: Create transaction header. Status is Cleared since bank confirms it.",
+      "_table": "Transactions",
+      "_operation": "add_records",
+      "payload": {
+        "Date": "{{date_timestamp}}",
+        "Description": "{{description}}",
+        "Reference": "{{reference}}",
+        "Status": "Cleared",
+        "Memo": "{{memo}}"
+      }
+    },
+    "transaction_lines": {
+      "_doc": "Step 2: Debit offset account, Credit Checking (asset decrease).",
+      "_table": "TransactionLines",
+      "_operation": "add_records",
+      "_requires": ["txn_id"],
+      "payload": [
+        {
+          "Transaction": "{{txn_id}}",
+          "Account": "{{offset_account_id}}",
+          "Debit": "{{amount}}",
+          "Credit": 0,
+          "Memo": "{{description}}"
+        },
+        {
+          "Transaction": "{{txn_id}}",
+          "Account": 14,
+          "Debit": 0,
+          "Credit": "{{amount}}",
+          "Memo": "{{description}}"
+        }
+      ]
+    }
+  },
+  "journal_entries": {
+    "_doc": "Summary of journal entry created by this template",
+    "entry": {
+      "description": "Record bank withdrawal",
+      "debits": [{"account": "Offset Account", "amount": "{{amount}}"}],
+      "credits": [{"account": "Checking Account (1001)", "amount": "{{amount}}"}]
+    }
+  },
+  "examples": {
+    "owner_draw": {
+      "description": "ATM withdrawal - owner draw",
+      "offset_account_id": 24,
+      "offset_account_name": "Owner's Draws (3002)"
+    },
+    "bank_fee": {
+      "description": "Bank service fee",
+      "offset_account_id": 30,
+      "offset_account_name": "Bank & Merchant Fees (5020)"
+    }
+  }
+}