fix: use raw RDB$FIELD_NAME key instead of alias for Firebird metadata query

app/routes/debug_fb.py

@@ -26,7 +26,7 @@ async def listar_diagnosticos(
 
         # Estructura de la tabla
         ok_c, _, cols = fb.execute_query(
-            "SELECT TRIM(f.RDB$FIELD_NAME) AS col "
+            "SELECT f.RDB$FIELD_NAME "
             "FROM RDB$RELATION_FIELDS f "
             "WHERE TRIM(f.RDB$RELATION_NAME) = 'DIAGNOSTICO' "
             "ORDER BY f.RDB$FIELD_POSITION", None
@@ -58,7 +58,7 @@ async def listar_diagnosticos(
         return JSONResponse({
             "ok":      True,
             "total":   cnt[0]["TOTAL"] if ok_n and cnt else "?",
-            "columnas": [c["col"] for c in cols] if ok_c and cols else [],
+            "columnas": [list(c.values())[0].strip() for c in cols] if ok_c and cols else [],
             "limite":  limit,
             "filtro":  q or None,
             "rows":    [{"cod": r["cod"], "concepto": r["concepto"]} for r in (rows or [])],