fix: address account valuation review findings

jarca_ledger_mcp/application/shared.py

@@ -5,6 +5,7 @@ import sqlite3 as sqlite3
 import hashlib
 import json
 import re
+from functools import wraps
 from datetime import date, datetime, timedelta
 from pathlib import Path
 from typing import Any
@@ -23,6 +24,8 @@ from ..infrastructure.parsers import (
 )
 from ..infrastructure.sqlite import db as db
 from ..infrastructure.sqlite import init_db as init_db
+from ..infrastructure.sqlite import read_db as read_db
+from ..infrastructure.sqlite import DatabaseNotInitializedError
 from ..infrastructure.sqlite import resolve_db_path as resolve_db_path
 
 VALID_TRANSACTION_TYPES = {"income", "expense", "transfer", "refund", "adjustment"}
@@ -121,6 +124,19 @@ def ok(**data: Any) -> dict[str, Any]:
 def fail(error_code: str, message: str, **data: Any) -> dict[str, Any]:
     return {"success": False, "error_code": error_code, "error": message, **data}
 
+
+def read_operation(function):
+    """Translate missing/read-only SQLite failures to the public envelope."""
+    @wraps(function)
+    def wrapped(*args, **kwargs):
+        try:
+            return function(*args, **kwargs)
+        except DatabaseNotInitializedError:
+            return fail("db_not_initialized", "ledger database is not initialized")
+        except sqlite3.Error:
+            return fail("db_error", "ledger database read failed")
+    return wrapped
+
 def row_to_dict(row: Any) -> dict[str, Any]:
     d = dict(row)
     if "tags" in d: