Fix fdb named parameter support: convert :name to positional ?

fdb does not support named parameters (:name + dict). Convert all
:name placeholders to ? and build a positional list from the param
dict in the same order they appear in the query.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/services/firebird_service.py

@@ -1,3 +1,4 @@
+import re
 import fdb
 import datetime
 import decimal
@@ -62,8 +63,15 @@ class FirebirdService:
             return False, "No hay conexión activa", []
         try:
             cur = self.conn.cursor()
-            if params is not None:
-                cur.execute(query, params)
+            if params:
+                # fdb no soporta :name — convertir a positional ?
+                param_names = re.findall(r':([a-zA-Z_][a-zA-Z0-9_]*)', query)
+                if param_names:
+                    positional_sql = re.sub(r':[a-zA-Z_][a-zA-Z0-9_]*', '?', query)
+                    positional_vals = [params[n] for n in param_names]
+                    cur.execute(positional_sql, positional_vals)
+                else:
+                    cur.execute(query)
             else:
                 cur.execute(query)
             columns = [desc[0] for desc in cur.description] if cur.description else []