## Summary
Refactor the Go `KnowledgeCompilerComponent` so its parameter is a
**single string template id** instead of a DSL-level `variant` (or
plural group id list). The `variant` is no longer in the DSL — it is now
**derived at runtime from the resolved compilation template's `kind`
field**.
This aligns the Go ingestion port with the frontend Compiler operator,
which emits a singular `compilation_template_group_id` and does not
write `variant` into the generated `compiler.json`.
### What problem does this PR solve?
- Clear stale pipeline IDs and generated data when updating documents
without `pipeline_id`.
- Support tree compilation results in pipeline workflows.
- Update compilation templates in place while preserving existing
template IDs.
- Improve duplicate-template validation messages.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
Co-authored-by: Jin Hai <haijin.chn@gmail.com>
