Add Karavan metadata + auto-generator for RosettaNet PIPs

[rdobrik]

Summary

Add Apache Karavan metadata for the RosettaNet component and all PIP JAXB models under
io.dscope.rosettanet.interchange, so they appear in the Karavan palette with form-based editing.

This includes:

1. Component metadata (rosettanet.json)
2. Model metadata (*.json, one per *RequestType/*ResponseType)
3. Generator tool to auto-create model metadata from JAXB classes
4. GitHub Action to detect drift and auto-open PRs

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Why

• Enables visual RosettaNet editing in Karavan
• No need to hand-maintain dozens of PIP structures
• Metadata always stays in sync with JAXB when models update
• Improves developer UX for B2B/Camel integration

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Acceptance Criteria ✅

• src/main/resources/karavan/metadata/component/rosettanet.json added
• src/main/resources/karavan/metadata/model/*.json generated for all *RequestType/*ResponseType
• src/main/resources/karavan/metadata/model-labels.json included (optional)
• io.dscope.tools.karavan.RosettaNetKaravanModelGenerator committed
• Maven profile -Pkaravan-metadata added to regenerate metadata
• GitHub workflow added: .github/workflows/generate-karavan-metadata.yml
• Workflow auto-creates PR if metadata changes

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Regenerate locally

mvn -Pkaravan-metadata -q exec:java \
  -Dexec.mainClass=io.dscope.tools.karavan.RosettaNetKaravanModelGenerator