[dajiaohuang]

Fixes #134.

Keep the public Glow XML exporter and importer consistent:

• Export the parameter field as isOnline, matching the importer, and import the existing default value.
• Import Template and QualifiedTemplate, preserving descriptions and their Node/Parameter/Matrix/Function element types with the required template-element tag.
• Return the actual GlowFunction type from ConvertFunction so the template-element conversion compiles without a cast or fallback.

Validation reuses the recorded native public-component run from 2026-10-15:

• Real GlowXmlExport -> GlowXmlImport round trips: baseline fails 7/7; corrected candidate passes 7/7 (IsOnline=false, default=5, four template element types and a qualified template).
• The original uncorrected candidate had CS0266 at the function return boundary. The included narrow return-type correction is the same one that passed the native component run.
• Both production files match the executed corrected source after line-end normalization. Only newly changed line endings were normalized for the default whitespace check; existing lines remain intact.
• The same public round-trip regression is included at tests/regressions/glow_xml_roundtrip.cs with a zero-mismatches exit condition. Staged whitespace check passed.

The validation used separate native BerLib/EmberLib/Glow libraries and the XML-only PowerPack component with unchanged helpers. It does not establish the original signed .NET Framework projects, full PowerPack/framing/formula integration, devices or hosted CI acceptance. No historical signed commit or signing key is added.