This commit introduces two main improvements to the Touka web framework:
1. **Configurable Request Body Size Limit:**
- Added `MaxRequestBodySize int64` to `touka.Engine` (default 10MB).
- You can customize this via `engine.SetMaxRequestBodySize()`.
- The context methods `GetReqBodyFull()`, `GetReqBodyBuffer()`, and `ShouldBindJSON()` now adhere to this limit. They check `Content-Length` upfront and use `http.MaxBytesReader` to prevent reading excessively large request bodies into memory, enhancing protection against potential DoS attacks or high memory usage.
- Added comprehensive unit tests in `context_test.go` for this feature, covering scenarios where the limit is active, disabled, and exceeded.
2. **Enhanced Error Logging in Default Handler:**
- The `defaultErrorHandle` in `engine.go` now logs not only the primary error passed to it but also any additional errors collected in `Context.Errors` (via `c.AddError()`).
- This provides more comprehensive diagnostic information in the logs without altering the JSON error response structure sent to the client, ensuring backward compatibility.
These changes aim to improve the framework's robustness, memory safety, and debuggability.
