docs: add build instructions to README (#174)

* docs: add build instructions to README

Resolves #7

Added comprehensive build documentation covering:
- Prerequisites (CMake 3.25+, C++20 compiler)
- Building included examples
- Integrating Aurora into game decomp projects
- Available CMake options

Verified on macOS with clang by successfully building the simple example.

* qa: fix --recursive flag (no submodules) and add missing AURORA_CACHE_USE_ZSTD option

- Remove --recursive from clone command: repo uses FetchContent, not submodules
- Document AURORA_CACHE_USE_ZSTD option (default: ON) that was missing from the list

* move build instructions to docs/building.md

README.md

@@ -38,6 +38,10 @@ implementation used is Chromium's [Dawn](https://dawn.googlesource.com/dawn/).
 
 ![Screenshot](assets/screenshot.png)
 
+### Building
+
+See [docs/building.md](docs/building.md) for build instructions, CMake integration, and configuration options.
+
 ### License
 
 Aurora is licensed under the [MIT License](LICENSE).

docs/building.md

@@ -0,0 +1,56 @@
+# Building
+
+## Prerequisites
+
+- CMake 3.25 or later
+- A C++20 compatible compiler (Clang, GCC, or MSVC)
+- Git (for cloning)
+
+## Building the Examples
+
+To build Aurora's included examples:
+
+```bash
+git clone https://github.com/encounter/aurora.git
+cd aurora
+mkdir build && cd build
+cmake ..
+cmake --build . --target simple
+```
+
+The `simple` example demonstrates a minimal Aurora application with a blue screen. The built executable will be in `build/examples/simple`.
+
+## Using Aurora in Your Project
+
+Aurora is designed to be integrated as a library in GameCube/Wii decompilation projects.
+
+**CMakeLists.txt example:**
+
+```cmake
+cmake_minimum_required(VERSION 3.25)
+project(your_game)
+
+# Add Aurora as a subdirectory
+add_subdirectory(extern/aurora EXCLUDE_FROM_ALL)
+
+# Create your executable
+add_executable(your_game src/main.c)
+
+# Link against Aurora components
+target_link_libraries(your_game PRIVATE 
+    aurora::core 
+    aurora::gx 
+    aurora::main 
+    aurora::vi
+)
+```
+
+See [examples/simple.c](../examples/simple.c) for a minimal application template.
+
+## CMake Options
+
+- `AURORA_ENABLE_GX` (default: ON) - Enable GX implementation and WebGPU renderer
+- `AURORA_ENABLE_DVD` (default: OFF) - Enable DVD implementation backed by nod
+- `AURORA_ENABLE_CARD` (default: ON) - Enable CARD implementation based on kabufuda
+- `AURORA_ENABLE_RMLUI` (default: OFF) - Enable HTML/CSS based UI library
+- `AURORA_CACHE_USE_ZSTD` (default: ON) - Compress WebGPU cache entries with zstd