Update GEMINI.md

This change improves the GEMINI.md file to provide better context for
AI agents working on the dcsctp library. This ensures generated code 
adheres to the library's design principles and reduces the likelihood of 
agents suggesting incompatible async or unsafe patterns.

Author: boivie

GEMINI.md

@@ -1,64 +1,55 @@
 # GEMINI.md
 
-This document provides important context about the `dcsctp` project for the Gemini AI assistant.
-
 ## Project Overview
 
-`dcsctp` is a Rust implementation of the Stream Control Transmission Protocol (SCTP) tailored for WebRTC Data Channels. It's a network programming library designed to be used in larger WebRTC applications.
-
-## Directory Structure
-
-*   `.github/`: Contains GitHub Actions workflows for continuous integration.
-*   `fuzz/`: Contains fuzzing targets and related files for testing the robustness of the parser.
-*   `src/`: The main source code for the `dcsctp` library.
-    *   `api/`: Public API definitions.
-    *   `events.rs`: Event definitions.
-    *   `fuzzer/`: Fuzzing-related utilities.
-    *   `lib.rs`: The main library file.
-    *   `packet/`: SCTP packet and chunk definitions and parsing logic.
-    *   `rx/`: Code related to receiving data.
-    *   `socket/`: The main SCTP socket implementation.
-    *   `testing/`: Testing utilities and data generators.
-    *   `timer.rs`: Timer-related logic.
-    *   `tx/`: Code related to sending data.
-    *   `types.rs`: Core data types used throughout the library.
-
-## Core Commands
-
-When working on this project, please use the following commands to ensure code quality and correctness.
-
-### Building the code
-
-To build the project, run:
-```bash
-cargo build
-```
-
-### Running tests
-
-The project has a comprehensive test suite. To run all tests, use:
-```bash
-cargo test
-```
-
-### Linting and formatting
-
-This project uses `rustfmt` for code formatting and `clippy` for linting.
-
-To check for formatting issues, run:
-```bash
-cargo +nightly fmt --all -- --check
-```
-
-To run the linter, use:
-```bash
-cargo clippy --all-features --all-targets -- -D warnings
-```
-
-## Project Conventions
-
-*   The project follows standard Rust conventions.
-*   All code should be formatted with `rustfmt`.
-*   All code should pass `clippy` checks with no warnings.
-*   New features should be accompanied by unit tests.
-*   Commit messages should be clear and descriptive.
+`dcsctp` is a Rust implementation of the Stream Control Transmission Protocol
+(SCTP, [RFC 9260](https://www.rfc-editor.org/rfc/rfc9260.txt)) designed for 
+WebRTC Data Channels ([RFC 8831](https://www.rfc-editor.org/rfc/rfc8831.txt)). 
+It is a user-space library intended to be embedded in larger systems (like 
+WebRTC  implementations), not a standalone server or in an operating system 
+kernel.
+
+## Architecture
+
+- **Core Design**: The library is single-threaded and event-driven. It does not
+  perform I/O directly. The consumer drives the loop by feeding packets/timer
+  events and handling outgoing commands.
+- **Entry Point**: The primary interface is the `DcSctpSocket` trait defined in 
+  `src/api/mod.rs`. Use `dcsctp::new_socket` (in `src/lib.rs`) to instantiate.
+- **Directory Structure**:
+  - `src/api/`: Public API and configuration options.
+  - `src/packet/`: Wire format parsing and serialization (Chunks, Parameters).
+  - `src/socket/`: Main state machine and socket logic.
+  - `src/rx/` & `src/tx/`: Receiver and Transmitter logic (reassembly,
+    congestion control).
+  - `src/timer/`: Timer abstractions (does not use system timers directly).
+  - `fuzz/`: Fuzz targets.
+- **C++ Bindings**: `src/ffi.rs` provides C++ bindings using `cxx`. Any changes
+  to the public API must also be added here.
+
+## Development Workflow
+
+- **Build**: `cargo build`
+- **Test**: `cargo test` (Runs extensive unit and integration tests).
+- **Lint**: `cargo clippy --all-features --all-targets -- -D warnings`
+- **Format**: `cargo +nightly fmt --all -- --check`
+
+## Coding Standards
+
+- **Safety**: `unsafe` code is strictly prohibited (`deny(unsafe_code)`).
+- **Error Handling**: Use `thiserror` for error types. Return
+  `Result<T, Error>` for fallible operations.
+- **Logging**: Use the `log` crate (`trace!`, `debug!`, `info!`, `warn!`,
+  `error!`). Do not use `println!`.
+- **Async**: The library is synchronous. Do not introduce `async/await` in core
+  logic.
+- **Dependencies**: Keep dependencies minimal. Major ones: `log`, `thiserror`,
+  `fastrand`.
+
+## Contribution Rules
+
+- **Changelog**: All functional changes must be documented in `CHANGELOG.md`
+  under the *Unreleased* section (categories: Added, Changed, Deprecated,
+  Removed, Fixed, Security).
+- **Commits**: Use clear, descriptive commit messages.
+- **Pull Requests**: One change per PR.