feat: Replace KIE Multiplying Architecture with a native host bridge

[lhein]

Description

Replace KIE Multiplying Architecture with a Kaoto-owned, typed host communication bridge for the web editor and VS Code extension.

Fixes #3938

• Introduce IEventBus, shared message contracts, and transports for VS Code webviews, browser iframes, and in-memory embedding, exported through @kaoto/kaoto/host-bridge.
• Migrate the desktop and web extension hosts and remove the KIE communication layer and runtime dependencies.
• Share document content, dirty/save state, and native undo/redo between the visual and source editors in VS Code. Standalone Kaoto Web retains its local history.
• UX improvement: Automatically select newly inserted steps and open their properties panel so users can configure them immediately.
• Keep selection and property forms stable during source edits across Canvas, Beans, and REST. Update REST service labels and fix duplicate property controls and canvas layout issues.

Includes a temporary @kaoto/forms patch for updating form models without remounting. The upstream fix is proposed in KaotoIO/forms#120.

Follow-up before marking ready for review

• Make startup retry recover when the webview takes longer than the initial host handshake deadline. Currently the host listener is disposed on timeout, while the Retry button only restarts the editor side; reopening the editor is required in this case.

Type of Change

• Bug fix
• New feature
• Improvement
• Documentation update
• Other

How Has This Been Tested?

• UI production build and library build.
• Full UI unit suite: 7,345 passed, 27 skipped, 2 todo.
• UI ESLint and stylelint.
• Extension development build, ESLint, and native VS Code unit tests: 484 passed.
• Native VS Code tab-switch and canvas toolbar tests: 5 passed.
• During implementation, focused native VS Code UI regressions passed for source updates in setBody expressions, AMQP endpoint properties, Beans, and REST Configuration/Service/Operation forms, including REST service ID changes.

Checklist

• I have read the Contributing Guidelines.
• I have followed the coding style and conventions of the project.
• I have tested my changes and recorded the remaining startup-retry issue above.
• I have updated any relevant documentation.
• I have added tests that prove my fix or feature works.

[coderabbitai]

Important

Draft PR not reviewed

Draft PRs are not automatically reviewed by default.

• Trigger a manual review

To automatically review draft PRs, update your CodeRabbit configuration:

reviews:
  auto_review:
    drafts: true

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.3% Duplication on New Code

See analysis details on SonarQube Cloud