First slice: ledger-store (journal+blobs+sqlite) and ledger-mcp (18 tools, receipt policy)

crates/ledger-core/src/account.rs

@@ -100,11 +100,11 @@ impl ChartOfAccounts {
         if self.by_code.contains_key(code) {
             return Err(LedgerError::DuplicateAccountCode(code.to_string()));
         }
-        if let Some(p) = parent {
-            if !self.accounts.contains_key(&p) {
+        if let Some(p) = parent
+            && !self.accounts.contains_key(&p)
+        {
             return Err(LedgerError::UnknownParentAccount(p));
         }
-        }
         self.by_code.insert(code.to_string(), id);
         self.accounts.insert(
             id,