docs: add build guides to the docs site

Author: auscaster

.gitignore

@@ -6,6 +6,8 @@ node_modules
 bak
 dist
 build*
+!docs/build/
+!docs/build/*.md
 private
 doxygen2md
 _book

docs/build/getting-started.md

@@ -0,0 +1,185 @@
+# Getting Started
+
+This page is the shortest path from zero to a working icey program.
+
+If you need every build knob, install prefix, or platform package detail, use the [installation guide](installation.md). If you are still figuring out which subsystem you need, start with the [module map](../modules.md).
+
+## Quick Start
+
+:::steps
+
+1. Add icey to your CMakeLists.txt
+
+   The fastest way to use icey is CMake FetchContent. No manual cloning, no system installation; CMake downloads and builds only the modules you need.
+
+   ```cmake
+   cmake_minimum_required(VERSION 3.21)
+   project(myapp)
+
+   include(FetchContent)
+   FetchContent_Declare(icey
+     GIT_REPOSITORY https://github.com/nilstate/icey.git
+     GIT_TAG 2.4.0
+   )
+   FetchContent_MakeAvailable(icey)
+
+   add_executable(myapp src/main.cpp)
+   target_link_libraries(myapp PRIVATE icey::base icey::net icey::http)
+   ```
+
+2. Link only what you need
+
+   Each module is a separate imported CMake target under the `icey::` namespace. Dependencies resolve automatically.
+
+3. Build
+
+   ```bash
+   cmake -B build -DCMAKE_BUILD_TYPE=Release
+   cmake --build build
+   ```
+
+:::
+
+## Available Targets
+
+| Target | Module | Optional Dependencies |
+| ------ | ------ | --------------------- |
+| `icey::base` | [Base](../modules/base.md) | — |
+| `icey::crypto` | [Crypto](../modules/crypto.md) | OpenSSL 3.x |
+| `icey::net` | [Net](../modules/net.md) | — |
+| `icey::http` | [HTTP](../modules/http.md) | — |
+| `icey::json` | [JSON](../modules/json.md) | — |
+| `icey::av` | [AV](../modules/av.md) | FFmpeg 5+/6+/7+ |
+| `icey::webrtc` | [WebRTC](../modules/webrtc.md) | libdatachannel |
+| `icey::symple` | [Symple](../modules/symple.md) | — |
+| `icey::stun` | [STUN](../modules/stun.md) | — |
+| `icey::turn` | [TURN](../modules/turn.md) | — |
+| `icey::archo` | [Archo](../modules/archo.md) | — |
+| `icey::pacm` | [Pacm](../modules/pacm.md) | — |
+| `icey::pluga` | [Pluga](../modules/pluga.md) | — |
+| `icey::sched` | [Sched](../modules/sched.md) | — |
+
+## Building from Source
+
+If you want a local build without installing system-wide:
+
+```bash
+git clone https://github.com/nilstate/icey.git
+cd icey
+cmake -B build -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTS=ON
+cmake --build build --parallel $(nproc)
+ctest --test-dir build --output-on-failure
+```
+
+Then use `find_package` in your project:
+
+```cmake
+find_package(icey REQUIRED)
+target_link_libraries(myapp PRIVATE icey::base icey::net icey::http)
+```
+
+See the [installation guide](installation.md) for the full build/install path, platform-specific dependencies, and CMake options.
+
+## Enabling Optional Modules
+
+icey auto-detects optional system dependencies and builds the matching modules when they are available.
+
+- **`icey::av`** (FFmpeg): install `libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libswresample-dev` (Ubuntu/Debian) or `ffmpeg` (Homebrew). Point CMake at a custom build with `-DFFmpeg_ROOT=/path/to/ffmpeg`. The `av` module builds when FFmpeg is found.
+- **`icey::webrtc`** (libdatachannel): requires the `av` prerequisites above plus libdatachannel. libdatachannel is fetched automatically via FetchContent when the `webrtc` module is enabled and its prerequisites are present.
+- **`icey::crypto`, `icey::net`, `icey::stun`, `icey::turn`** (OpenSSL): install `libssl-dev` (Ubuntu/Debian) or `openssl` (Homebrew). These modules build when OpenSSL is found.
+
+For the full build matrix and all user-settable options, use [installation.md](installation.md).
+
+## What You Can Build
+
+### Stream a webcam to any browser
+
+150 lines of C++. Camera capture, H.264 encoding, WebRTC transport, Symple signalling. Open a browser, see video.
+
+```cpp
+session.IncomingCall += [&](const std::string& peerId) {
+    session.accept();
+};
+
+session.StateChanged += [&](wrtc::PeerSession::State state) {
+    if (state == wrtc::PeerSession::State::Active) {
+        stream.attachSource(capture.get());
+        stream.attach(&session->media().videoSender(), 5);
+        stream.start();
+    }
+};
+```
+
+See [`webcam-streamer`](https://github.com/nilstate/icey/tree/main/src/webrtc/samples/webcam-streamer/) or read [WebRTC in 150 Lines of C++](https://0state.com/writing/webrtc-in-150-lines-of-cpp).
+
+### Record a browser's camera server-side
+
+Browser sends WebRTC, your C++ server decodes with FFmpeg, writes to any format. Server-side recording without cloud vendor lock-in.
+
+See [`media-recorder`](https://github.com/nilstate/icey/tree/main/src/webrtc/samples/media-recorder/).
+
+### Media pipeline
+
+Camera to encoder to network in four lines:
+
+```cpp
+PacketStream stream;
+stream.attachSource(videoCapture);
+stream.attach(new av::MultiplexPacketEncoder(opts), 5);
+stream.attach(socket, 10);
+stream.start();
+```
+
+### WebRTC peer session
+
+```cpp
+wrtc::PeerSession::Config config;
+config.rtcConfig.iceServers.emplace_back("stun:stun.l.google.com:19302");
+config.media.videoCodec = av::VideoCodec("H264", "libx264", 1280, 720, 30);
+
+wrtc::SympleSignaller signaller(client);
+wrtc::PeerSession session(signaller, config);
+
+session.IncomingCall += [&](const std::string& peerId) {
+    session.accept();
+};
+
+session.StateChanged += [&](wrtc::PeerSession::State state) {
+    if (state == wrtc::PeerSession::State::Active)
+        startStreaming(session);
+};
+```
+
+## Your First Program
+
+A minimal HTTP echo server:
+
+```cpp
+#include "icy/http/server.h"
+#include "icy/loop.h"
+
+int main() {
+    icy::http::Server srv{"0.0.0.0", 8080};
+    srv.Connection += [](icy::http::ServerConnection::Ptr conn) {
+        conn->Payload += [](icy::http::ServerConnection& conn,
+                            const icy::MutableBuffer& buf) {
+            conn.send(icy::bufferCast<const char*>(buf), buf.size());
+            conn.close();
+        };
+    };
+    srv.start();
+    icy::uv::runLoop();
+    return 0;
+}
+```
+
+## Next Steps
+
+- Read the [module map](../modules.md) if you want the dependency picture first.
+- Go straight to a guide if you know the subsystem:
+  - [Base](../modules/base.md)
+  - [HTTP](../modules/http.md)
+  - [WebRTC](../modules/webrtc.md)
+  - [TURN](../modules/turn.md)
+- Explore the samples and apps in each module's `src/*/samples` or `src/*/apps` directories.
+- Read the [contributing guide](../contributing.md) if you want to work on icey itself.