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/Incremental/Incremental.cpp

@@ -0,0 +1,73 @@
+/*
+Crafter® Build
+Copyright (C) 2026 Catcrafts®
+Catcrafts.net
+
+LGPL-3.0-only.
+*/
+
+import std;
+import Crafter.Build;
+#include "../_shared/TestUtil.h"
+namespace fs = std::filesystem;
+using namespace std::chrono_literals;
+using namespace TestUtil;
+using namespace Crafter;
+
+int main() {
+    try {
+        fs::path src = fs::current_path() / "tests" / "Incremental" / "inner";
+        Configuration cfg = LoadFixture("Incremental", src);
+        fs::path work = fs::current_path();
+
+        auto cold = BuildOnce(cfg);
+        if (!cold.result.empty()) {
+            std::println(std::cerr, "cold build failed:\n{}", cold.result);
+            return 1;
+        }
+
+        fs::path buildDir = work / "build" / "hello-mod-x86_64-pc-linux-gnu-native";
+        fs::path greeterObj = buildDir / "Greeter.o";
+        fs::path mainObj    = buildDir / "main_impl.o";
+        if (!fs::exists(greeterObj) || !fs::exists(mainObj)) {
+            std::println(std::cerr, "expected .o files missing after cold build");
+            return 1;
+        }
+        auto greeter_t1 = fs::last_write_time(greeterObj);
+        auto main_t1    = fs::last_write_time(mainObj);
+
+        auto noop = BuildOnce(cfg);
+        if (!noop.result.empty()) {
+            std::println(std::cerr, "no-op rebuild failed:\n{}", noop.result);
+            return 1;
+        }
+        if (fs::last_write_time(greeterObj) != greeter_t1) {
+            std::println(std::cerr, "no-op rebuild regenerated Greeter.o");
+            return 1;
+        }
+        if (fs::last_write_time(mainObj) != main_t1) {
+            std::println(std::cerr, "no-op rebuild regenerated main_impl.o");
+            return 1;
+        }
+
+        // Touch main.cpp: only main_impl.o should regenerate.
+        fs::last_write_time(work / "main.cpp", std::chrono::file_clock::now() + 2s);
+        auto touched = BuildOnce(cfg);
+        if (!touched.result.empty()) {
+            std::println(std::cerr, "rebuild after touch failed:\n{}", touched.result);
+            return 1;
+        }
+        if (fs::last_write_time(greeterObj) != greeter_t1) {
+            std::println(std::cerr, "touching main.cpp unnecessarily rebuilt Greeter.o");
+            return 1;
+        }
+        if (fs::last_write_time(mainObj) <= main_t1) {
+            std::println(std::cerr, "touching main.cpp did NOT rebuild main_impl.o");
+            return 1;
+        }
+        return 0;
+    } catch (const std::exception& e) {
+        std::println(std::cerr, "test exception: {}", e.what());
+        return 1;
+    }
+}