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/wasi/README.md

@@ -0,0 +1,40 @@
+# WASI
+
+Build a C++26 program for the `wasm32-wasi` target and run it in a browser.
+
+## Prerequisites
+
+- `wasi-libc`, `wasi-libc++`, `wasi-libc++abi` (Arch packages — provide
+  `/usr/share/wasi-sysroot/`, which `crafter-build` finds automatically).
+  Other distros: install the WASI SDK and set `cfg.sysroot` in `project.cpp`.
+
+## Build
+
+```bash
+crafter-build
+```
+
+Output lands in `bin/wasi-hello-wasm32-wasip1-native/`:
+
+- `wasi-hello.wasm` — the compiled module
+- `index.html` + `runtime.js` — a minimal in-browser WASI shim, dropped in by
+  `EnableWasiBrowserRuntime(cfg)` in `project.cpp`. Stdout goes to the browser
+  console.
+
+## Run in a browser
+
+```bash
+./serve.sh                  # any static file server works
+```
+
+Open `http://localhost:8080/`. The string from `main()` shows up in the
+DevTools console.
+
+## Run in a standalone runtime
+
+If you don't need the browser, drop the `EnableWasiBrowserRuntime(cfg)` line
+from `project.cpp` and run the `.wasm` directly:
+
+```bash
+wasmtime bin/wasi-hello-wasm32-wasip1-native/wasi-hello.wasm
+```

examples/wasi/main.cpp

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+import std;
+
+int main() {
+    std::println("Hello, WASI!");
+    return 0;
+}

examples/wasi/project.cpp

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+import std;
+import Crafter.Build;
+namespace fs = std::filesystem;
+using namespace Crafter;
+
+extern "C" Configuration CrafterBuildProject(std::span<const std::string_view>) {
+    Configuration cfg;
+    cfg.path = "./";
+    cfg.name = "wasi-hello";
+    cfg.outputName = "wasi-hello";
+    cfg.target = "wasm32-wasip1";
+    cfg.type = ConfigurationType::Executable;
+
+    std::array<fs::path, 0> ifaces = {};
+    std::array<fs::path, 1> impls = { "main" };
+    cfg.GetInterfacesAndImplementations(ifaces, impls);
+
+    // Drop a small index.html + runtime.js next to the .wasm so a static file
+    // server is enough to run it in the browser. Skip this call when targeting
+    // a standalone runtime like wasmtime — you don't need the shim then.
+    EnableWasiBrowserRuntime(cfg);
+
+    return cfg;
+}

examples/wasi/serve.sh

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+#!/usr/bin/env sh
+caddy file-server --listen :8080 --root bin/wasi-hello-wasm32-wasip1-native