[Fix] (MG_Util, MG_State): five latent frontend bugs the async work made load-bearing

- SpvcSession's move constructor and move assignment dropped the parsed
  metadata, so a moved-to session silently reported empty reflection.
- ParseComputeLocalSize used std::stoull, whose std::out_of_range escaped
  glCompileShader on an oversized local_size literal; now std::from_chars
  saturating to UINT_MAX, pinned by a regression test that reproduced the
  escaping exception.
- The compute local_size std::regex was rebuilt on every compile; hoisted.
- LinkProgram dumped every shader's full source through MGLOG_D per link.
- glslang::FinalizeProcess ran before the GL context tore down, leaving the
  context's live TShaders pointing at freed builtin symbol tables.

MobileGL/MG_Util/ShaderTranspiler/SpvcSession.cpp

@@ -138,6 +138,9 @@ namespace MobileGL {
                 std::swap(this->resources, that.resources);
                 std::swap(this->reflectModule, that.reflectModule);
                 std::swap(this->reflectModuleValid, that.reflectModuleValid);
+                // ParseMetaData() fills `metadata`, and GetMetadata() is read through the
+                // moved-to session: leaving it behind silently returns an empty reflection.
+                std::swap(this->metadata, that.metadata);
             }
 
             SpvcSession& SpvcSession::operator=(SpvcSession&& that) {
@@ -149,6 +152,7 @@ namespace MobileGL {
                 std::swap(this->resources, that.resources);
                 std::swap(this->reflectModule, that.reflectModule);
                 std::swap(this->reflectModuleValid, that.reflectModuleValid);
+                std::swap(this->metadata, that.metadata);
                 return *this;
             }