fix: improve Python step error messages for better debugging

[DragonBot00]

Summary

Fixes #5327

Problem

When a workflow uses a Python step provider and the code contains a syntax error, the error message was extremely unclear. Instead of surfacing the actual Python SyntaxError, Keep would dump the entire rendered provider config string (including unrelated details like Kibana endpoints, ports, and validation tokens) as the error message.

Example of the confusing error (before this fix):
\
Got SyntaxError while parsing token 'keep.kb.us-central1.gcp.cloud.es.io', 'validation': 'any_http_url'...
\\

This message has nothing to do with the user's Python code and is actively misleading.

Root Cause

In \python_provider.py, the _query\ method calls \self.io_handler.parse(code)\ to render Jinja templates inside the code string. When this rendering fails with a \SyntaxError\ (or when the rendered code fails inside \eval()), the exception message includes the raw rendered token — which can contain provider configuration data (URLs, authentication tokens, ports, etc.) from the workflow context.

Fix

• Pre-validation: Added a \compile()\ check on the raw user code before template rendering to catch syntax errors early with a clear message.
• Specific \SyntaxError\ handling on \io_handler.parse(): If rendering raises a \SyntaxError, we now surface the exact error message and line number without leaking provider config details.
• Specific \SyntaxError\ handling on \eval(): If the rendered code fails to evaluate with a \SyntaxError, we show the error with line number and a short preview of the rendered code (capped at 200 chars) for context.

Example of the improved error (after this fix):
\
SyntaxError in Python step 'my-python-step': invalid syntax (line 3)
\\

Testing

Manual verification that:

• Valid Python expressions continue to work correctly
• Syntax errors in user code now produce clear, actionable error messages
• Provider config data is no longer leaked in error messages

[DragonBot00]

I have read the CLA Document and I hereby sign the CLA

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[TheCodingDragon0]

Closing — no maintainer engagement after 5 days. Shifting focus to quality over quantity.

[DragonBot00]

Closing — no maintainer engagement after 5 days. Shifting focus to quality over quantity.