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-deposit.json

@@ -0,0 +1,86 @@
+{
+  "_meta": {
+    "name": "Bank Import - Deposit",
+    "description": "Record a deposit found in bank statement but missing from the ledger",
+    "scenario": "Unmatched bank deposit (interest, incoming transfer, revenue)",
+    "when_to_use": [
+      "Bank interest payments",
+      "Incoming transfers from owner",
+      "Revenue deposits",
+      "Any bank credit not yet in the ledger"
+    ],
+    "when_not_to_use": [
+      "Deposits already recorded in the ledger",
+      "Vendor refunds with existing bill records"
+    ]
+  },
+  "_variables": {
+    "date_timestamp": "integer - Unix timestamp for transaction date",
+    "amount": "number - Deposit amount (positive)",
+    "offset_account_id": "integer - Account to credit (e.g., 23=Owner's Investment, 25=Service Revenue)",
+    "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 Checking, Cr Offset Account)",
+    "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 Checking (asset increase), Credit offset account.",
+      "_table": "TransactionLines",
+      "_operation": "add_records",
+      "_requires": ["txn_id"],
+      "payload": [
+        {
+          "Transaction": "{{txn_id}}",
+          "Account": 14,
+          "Debit": "{{amount}}",
+          "Credit": 0,
+          "Memo": "{{description}}"
+        },
+        {
+          "Transaction": "{{txn_id}}",
+          "Account": "{{offset_account_id}}",
+          "Debit": 0,
+          "Credit": "{{amount}}",
+          "Memo": "{{description}}"
+        }
+      ]
+    }
+  },
+  "journal_entries": {
+    "_doc": "Summary of journal entry created by this template",
+    "entry": {
+      "description": "Record bank deposit",
+      "debits": [{"account": "Checking Account (1001)", "amount": "{{amount}}"}],
+      "credits": [{"account": "Offset Account", "amount": "{{amount}}"}]
+    }
+  },
+  "examples": {
+    "interest_income": {
+      "description": "Interest Paid",
+      "offset_account_id": 26,
+      "offset_account_name": "Interest Income (4010)"
+    },
+    "owner_transfer": {
+      "description": "Transfer from owner",
+      "offset_account_id": 23,
+      "offset_account_name": "Owner's Investment (3001)"
+    }
+  }
+}