♻️ refactor lua_push_interface and add json module

Refactor pushInterfaceToLua to delegate unsupported types (nil, bool/int/float/string/map/slice) recursively via new lvalueFromInterface helper. Simplify typed slice and map handlers, remove explicit nil case (now handled by lvalueFromInterface), eliminate redundant type switches in pushMapStringIntToLua and similar functions. Add new luajson.go with RegisterJSON, lua.JSONEncode/Decode bindings using lvalueFromInterface and Table2 Interface for bidirectional round-trips. Include comprehensive tests covering scalars, nested structures (e.g., kmindex response), arrays and error cases.

pkg/obilua/lua_table.go

@@ -28,6 +28,8 @@ func Table2Interface(interpreter *lua.LState, table *lua.LTable) interface{} {
 				val[i-1] = float64(v.(lua.LNumber))
 			case lua.LTString:
 				val[i-1] = string(v.(lua.LString))
+			case lua.LTTable:
+				val[i-1] = Table2Interface(interpreter, v.(*lua.LTable))
 			}
 		}
 		return val
@@ -45,6 +47,8 @@ func Table2Interface(interpreter *lua.LState, table *lua.LTable) interface{} {
 					val[string(ks)] = float64(v.(lua.LNumber))
 				case lua.LTString:
 					val[string(ks)] = string(v.(lua.LString))
+				case lua.LTTable:
+					val[string(ks)] = Table2Interface(interpreter, v.(*lua.LTable))
 				}
 			}
 		})