docs: add Linux (WSL/Ubuntu) quick start and build/test instructions

README.md

@@ -70,6 +70,60 @@ cmake -S example -B example/build -DCMAKE_BUILD_TYPE=Release
 cmake --build example/build --config Release
 ```
 
+### Linux (WSL/Ubuntu) – Quick start
+
+Prerequisites (Ubuntu/Debian):
+
+```bash
+sudo apt-get update -y && sudo apt-get install -y \
+  build-essential cmake git pkg-config libcurl4-openssl-dev \
+  curl zip unzip tar ninja-build ca-certificates
+```
+
+Bootstrap vcpkg (once):
+
+```bash
+git clone https://github.com/microsoft/vcpkg.git "$HOME/vcpkg"
+"$HOME/vcpkg/bootstrap-vcpkg.sh" -disableMetrics
+```
+
+Build (library, tests, example):
+
+```bash
+export VCPKG_ROOT="$HOME/vcpkg"
+cmake -S . -B build -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE="$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake"
+cmake --build build --config Release
+```
+
+Or simply use the helper script:
+
+```bash
+bash ./build.sh
+```
+
+Run the example:
+
+```bash
+./build/example/example
+```
+
+Run tests:
+
+```bash
+ctest --test-dir build --output-on-failure
+```
+
+Artifacts:
+
+- Library: `build/libprivatebinapi.so`
+- Example binary: `build/example/example`
+
+Notes:
+
+- vcpkg dependencies (`cryptopp`, `nlohmann-json`) are installed automatically during CMake configure when the toolchain file is provided.
+- On Linux the example links directly against the in-tree target `privatebinapi`. On Windows it additionally copies the DLL next to the example executable after build.
+- PrivateBin delete operation is performed via HTTP POST (per API), not HTTP DELETE.
+
 ### Windows (PowerShell) – Build via build_thinkpad.bat
 
 For systems with Visual Studio 2022 Build Tools (C++ workload) and vcpkg in the user profile, there is a robust build script: