ArgQuery: out-of-line CRAFTER_API methods for Windows DLL crossing

In-class inline methods on a module-exported class get the @<module>
linkage attachment, and clang does not emit their bodies into
consumers; the resulting external reference fails to resolve when a
project.dll on Windows tries to call ArgQuery::Has after consuming
ApplyStandardArgs's return value. Move the bodies to the implementation
unit and dllexport them.

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

implementations/Crafter.Build-Clang.cpp

@@ -865,6 +865,18 @@ std::string Crafter::HostTarget() {
     return cached;
 }
 
+bool Crafter::ArgQuery::Has(std::string_view flag) const {
+    for (std::string_view a : args) if (a == flag) return true;
+    return false;
+}
+
+std::optional<std::string> Crafter::ArgQuery::Get(std::string_view prefix) const {
+    for (std::string_view a : args) {
+        if (a.starts_with(prefix)) return std::string(a.substr(prefix.size()));
+    }
+    return std::nullopt;
+}
+
 ArgQuery Crafter::ApplyStandardArgs(Configuration& cfg, std::span<const std::string_view> args) {
     if (const char* envMarch = std::getenv("CRAFTER_BUILD_MARCH"); envMarch && *envMarch) {
         cfg.march = envMarch;