V2: WASI, -r flag, CI pipeline, examples & tests cleanup

WASI / wasm32 target support
- Auto-detect /usr/share/wasi-sysroot on Linux when target starts_with("wasm32")
- Skip -march/-mtune for wasm (clang rejects them)
- Apply -fno-exceptions -fno-c++-static-destructors -mllvm -wasm-enable-sjlj
  -D_WASI_EMULATED_SIGNAL to wasm builds (compile + std PCM, kept in sync)
- .wasm output extension in expectedOutputFor and link command
- EnableWasiBrowserRuntime(cfg): opt-in helper that drops index.html +
  runtime.js next to the .wasm; runtime.js reads window.CRAFTER_WASM_URL
  set in the templated index.html so a single shim handles any output name

-r run flag in the CLI: build then exec the artifact (host targets only;
  rejects libraries; auto .exe/.wasm extension handling)

CI pipeline (.forgejo/workflows/ci.yaml)
- Triggers: PR/push to master + manual dispatch
- Single arch-latest container job: install deps, bootstrap, self-rebuild,
  run tests, cross-compile mingw, package both archives, upload artifacts
- Rolling 'latest' release published only on push/dispatch to master

mingw cross-compile from Linux now works end-to-end:
- ExternalDependency cache key includes target so per-target glslang builds
  don't collide; CMAKE_BUILD_TYPE=Release pinned (otherwise glslang appends
  'd' to lib names and breaks linking); cross-compile cmake flags
  (CMAKE_SYSTEM_NAME=Windows, CMAKE_*_COMPILER_TARGET=...)
- project.cpp accepts --target=<triple>; Linux-only -Wl,--export-dynamic
  and -ldl are gated; mingw glslang skips the standalone exe (its libgcc_eh
  link pulls pthread which mingw doesn't link by default)
- mingw compile uses -femulated-tls so std::__once_callable etc reference
  the same emutls symbols libstdc++ provides
- mingw link auto-adds -lstdc++exp -lpthread

GetCrafterBuildHome() exposed from the Platform module; LoadProject (Linux
+ Windows) now both use it instead of duplicating the resolution.

Examples reorg: hello-world, library, with-module, wasi, tests — each with
its own README. Tests reorg: per-test directory with inner/ fixture, no
shared tests/fixtures/ tree. New Wasi test verifies .wasm magic bytes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

examples/library/README.md

@@ -0,0 +1,21 @@
+# library
+
+A static library + an executable that consumes it.
+
+```sh
+cd examples/library
+crafter-build
+./bin/math-app-x86_64-pc-linux-gnu-native/math-app
+```
+
+Layout:
+
+```
+mylib/MyMath.cppm     # the library's module interface
+main.cpp              # the consumer
+project.cpp           # declares both, with cfg.dependencies wiring them
+```
+
+Two `Configuration` objects: a `LibraryStatic` and an `Executable` whose `dependencies` points at the lib. The build runs them in parallel and links `libMyMath.a` into `math-app` automatically. `import MyMath;` in `main.cpp` resolves through the dep graph — no header paths to hand-wire.
+
+The `static unique_ptr<Configuration>` for the lib is the canonical lifetime pattern: the parent's `dependencies` is `vector<Configuration*>` (raw), so something needs to keep the lib alive across the function return. File-local `static` does it cleanly without a global pool.

examples/library/main.cpp

@@ -0,0 +1,8 @@
+import std;
+import MyMath;
+
+int main() {
+    std::println("Square(5) = {}", Square(5));
+    std::println("Cube(3)   = {}",  Cube(3));
+    return 0;
+}

examples/library/mylib/MyMath.cppm

@@ -0,0 +1,5 @@
+export module MyMath;
+import std;
+
+export int Square(int x) { return x * x; }
+export int Cube(int x)   { return x * x * x; }

examples/library/project.cpp

@@ -0,0 +1,37 @@
+import std;
+import Crafter.Build;
+namespace fs = std::filesystem;
+using namespace Crafter;
+
+extern "C" Configuration CrafterBuildProject(std::span<const std::string_view>) {
+    // The library — built into mylib/bin/MyMath-<target>-<march>/libMyMath.a
+    // and exposed to consumers via cfg.dependencies. The static unique_ptr
+    // keeps the Configuration alive for the duration of the build (the
+    // consumer holds a raw pointer to it).
+    static auto lib = std::make_unique<Configuration>();
+    lib->path = "./mylib/";
+    lib->name = "MyMath";
+    lib->outputName = "MyMath";
+    lib->target = "x86_64-pc-linux-gnu";
+    lib->type = ConfigurationType::LibraryStatic;
+    {
+        std::array<fs::path, 1> ifaces = { "MyMath" };
+        std::array<fs::path, 0> impls = {};
+        lib->GetInterfacesAndImplementations(ifaces, impls);
+    }
+
+    // The consumer — main.cpp imports MyMath. The build resolves the import
+    // through cfg.dependencies and links libMyMath.a automatically.
+    Configuration cfg;
+    cfg.path = "./";
+    cfg.name = "math-app";
+    cfg.outputName = "math-app";
+    cfg.target = "x86_64-pc-linux-gnu";
+    cfg.type = ConfigurationType::Executable;
+    cfg.dependencies = { lib.get() };
+
+    std::array<fs::path, 0> ifaces = {};
+    std::array<fs::path, 1> impls  = { "main" };
+    cfg.GetInterfacesAndImplementations(ifaces, impls);
+    return cfg;
+}