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/CrossArchAarch64/CrossArchAarch64.cpp

@@ -0,0 +1,78 @@
+/*
+Crafter® Build
+Copyright (C) 2026 Catcrafts®
+Catcrafts.net
+
+LGPL-3.0-only.
+
+End-to-end cross-arch build through the V2 pipeline:
+the inner project.cpp targets aarch64-linux-gnu with cfg.sysroot pointing at
+the Arch Linux ARM rootfs at /opt/aarch64-rootfs. crafter.build-lib
+cross-compiles the C++ source (with the libc++ std module from the sysroot),
+produces a real aarch64 ELF, and qemu-aarch64 (with QEMU_LD_PREFIX pointing at
+the sysroot so it can find ld-linux-aarch64.so.1) executes it.
+*/
+
+import std;
+import Crafter.Build;
+#include "../_shared/TestUtil.h"
+namespace fs = std::filesystem;
+using namespace TestUtil;
+using namespace Crafter;
+
+namespace {
+    bool ToolPresent(std::string_view name) {
+        return std::system(std::format("which {} > /dev/null 2>&1", name).c_str()) == 0;
+    }
+}
+
+int main() {
+    try {
+        const fs::path sysroot = "/opt/aarch64-rootfs";
+        if (!fs::exists(sysroot / "usr/share/libc++/v1/std.cppm")) {
+            Skip(std::format("aarch64 sysroot missing at {} — see README", sysroot.string()));
+        }
+        if (!ToolPresent("qemu-aarch64")) Skip("qemu-aarch64 not on PATH");
+
+        fs::path src = fs::current_path() / "tests" / "CrossArchAarch64" / "inner";
+        Configuration cfg = LoadFixture("CrossArchAarch64", src);
+        fs::path work = fs::current_path();
+
+        auto br = BuildOnce(cfg);
+        if (!br.result.empty()) {
+            std::println(std::cerr, "build failed:\n{}", br.result);
+            return 1;
+        }
+
+        fs::path artifact = work / "bin" / "aarch-hello-aarch64-linux-gnu-armv8-a" / "aarch-hello";
+        if (!fs::exists(artifact)) {
+            std::println(std::cerr, "expected artifact missing at {}", artifact.string());
+            return 1;
+        }
+
+        // Defend against silent host-arch fallback.
+        auto probe = RunInDir(work, std::format("file '{}'", artifact.string()));
+        if (probe.output.find("ARM aarch64") == std::string::npos) {
+            std::println(std::cerr, "artifact is not ARM aarch64 ELF:\n{}", probe.output);
+            return 1;
+        }
+
+        // Run via qemu-aarch64. QEMU_LD_PREFIX tells qemu where the target's
+        // dynamic linker (ld-linux-aarch64.so.1) and shared libs live.
+        auto run = RunInDir(work, std::format(
+            "QEMU_LD_PREFIX={} qemu-aarch64 '{}'",
+            sysroot.string(), artifact.string()));
+        if (run.exitCode != 0) {
+            std::println(std::cerr, "qemu-aarch64 run failed (rc={}):\n{}", run.exitCode, run.output);
+            return 1;
+        }
+        if (run.output != "hi from 64-bit aarch64\n") {
+            std::println(std::cerr, "output mismatch:\n  expected: \"hi from 64-bit aarch64\\n\"\n  got: {:?}", run.output);
+            return 1;
+        }
+        return 0;
+    } catch (const std::exception& e) {
+        std::println(std::cerr, "test exception: {}", e.what());
+        return 1;
+    }
+}

tests/CrossArchAarch64/inner/main.cpp

@@ -0,0 +1,6 @@
+import std;
+
+int main() {
+    std::println("hi from {}-bit aarch64", sizeof(void*) * 8);
+    return 0;
+}

tests/CrossArchAarch64/inner/project.cpp

@@ -0,0 +1,23 @@
+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 = "aarch-hello";
+    cfg.outputName = "aarch-hello";
+    cfg.target = "aarch64-linux-gnu";
+    cfg.march = "armv8-a";
+    cfg.mtune = "generic";
+    cfg.sysroot = "/opt/aarch64-rootfs";
+    cfg.type = ConfigurationType::Executable;
+
+    std::array<fs::path, 0> ifaces = {};
+    std::array<fs::path, 1> impls = { "main" };
+    cfg.GetInterfacesAndImplementations(ifaces, impls);
+
+
+    return cfg;
+}

tests/CrossArchAarch64/project.cpp

@@ -0,0 +1,20 @@
+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 = "tests/CrossArchAarch64/";
+    cfg.name = "CrossArchAarch64";
+    cfg.outputName = "CrossArchAarch64";
+    cfg.target = "x86_64-pc-linux-gnu";
+    cfg.type = ConfigurationType::Executable;
+    cfg.dependencies = { ParentLib("crafter.build-lib") };
+    cfg.linkFlags.push_back("-Wl,--export-dynamic");
+    cfg.linkFlags.push_back("-ldl");
+    std::array<fs::path, 0> ifaces = {};
+    std::array<fs::path, 1> impls = { "CrossArchAarch64" };
+    cfg.GetInterfacesAndImplementations(ifaces, impls);
+    return cfg;
+}