Fix(python): Element.highlight() missing from client

[Jhoan0714]

Summary

This PR Fixes #208 - the missing Element.highlight() method to the Python client (async and sync).

el.highlight() is documented in docs/reference/api.md, implemented in the Go backend (vibium:element.highlight), and available in the Java client — but was absent from vibium.async_api.Element and vibium.sync_api.Element.

Root Cause

Element.highlight() was documented and supported by the Go backend and Java client, but had not yet been exposed on the Python Element class.

Changes

clients/python/src/vibium/async_api/element.py

• Added async def highlight(self) -> None in the Interaction section (after set_files, before State queries)
• Sends vibium:element.highlight with standard _command_params() (context, selector, index, semantic params)
• No timeout parameter — matches Java and the backend handler, which uses instant evalElementScript rather than actionability polling

clients/python/src/vibium/sync_api/element.py

• Added sync wrapper delegating to the async implementation via _loop.run()

tests/py/test_interaction.py

• Added test_highlight smoke test: resolves #info, calls highlight(), verifies the BiDi command succeeds without error (same intent as Java's highlightIsImplemented in JavaClusterFixTest)

Why this matters

This closes a parity gap between the documented API and the Python client. Now python users can call el.highlight() as documented, consistent with the Java client and CLI.

Validation

Executed:

pytest tests/py/test_interaction.py -k highlight -v