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>

tests/CrossProjectModule/lib/Foo.cppm

@@ -0,0 +1,5 @@
+export module Foo;
+
+export int Compute() {
+    return 7 * 6;
+}

tests/CrossProjectModule/main.cpp

@@ -0,0 +1,7 @@
+import std;
+import Foo;
+
+int main() {
+    if (Compute() != 42) return 1;
+    return 0;
+}

tests/CrossProjectModule/project.cpp

@@ -0,0 +1,36 @@
+import std;
+import Crafter.Build;
+namespace fs = std::filesystem;
+using namespace Crafter;
+
+extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> args) {
+    std::string target = "x86_64-pc-linux-gnu";
+    for (auto a : args) {
+        if (a.starts_with("--target=")) target = std::string(a.substr(9));
+    }
+
+    static auto fooLib = std::make_unique<Configuration>();
+    fooLib->path = "tests/CrossProjectModule/lib/";
+    fooLib->name = std::format("Foo-{}", target);
+    fooLib->outputName = "Foo";
+    fooLib->target = target;
+    fooLib->type = ConfigurationType::LibraryStatic;
+    {
+        std::array<fs::path, 1> ifaces = { "Foo" };
+        std::array<fs::path, 0> impls = {};
+        fooLib->GetInterfacesAndImplementations(ifaces, impls);
+    }
+
+    Configuration cfg;
+    cfg.path = "tests/CrossProjectModule/";
+    cfg.name = "CrossProjectModule";
+    cfg.outputName = "cross-app";
+    cfg.target = target;
+    cfg.type = ConfigurationType::Executable;
+    cfg.dependencies = { fooLib.get() };
+
+    std::array<fs::path, 0> ifaces = {};
+    std::array<fs::path, 1> impls = { "main" };
+    cfg.GetInterfacesAndImplementations(ifaces, impls);
+    return cfg;
+}