fix: handle SyntaxError gracefully in ast_analyzer

[jyotish6699]

Description

This PR fixes a bug in the AST analyzer where invalid Python source code causes analyze() to raise a SyntaxError instead of returning a structured analyzer issue.

The analyzer currently crashes when malformed Python code is passed to ast.parse(). This behavior interrupts analysis and requires callers to handle unexpected exceptions.

With this change, syntax errors are handled gracefully and returned through the analyzer's existing issue-reporting system.

Changes Made

• Added SyntaxError handling around ast.parse()
• Return a structured analyzer issue when parsing fails
• Added test coverage for syntax-error handling
• Preserved existing analyzer behavior for valid Python code

Example

Before

analyze(
"""
def f(:
    pass
"""
)

Result:

SyntaxError: invalid syntax

After

The analyzer returns a structured issue describing the syntax error instead of crashing.

Related Issue

Fixes #741

Testing

Added:

• test_analyze_handles_syntax_error

Verified:

• Invalid Python syntax returns a structured analyzer issue
• Existing analyzer functionality remains unchanged
• Tests pass successfully

Notes

This issue is different from #466.

Issue #466 focuses on adding test coverage for existing AST analyzer behaviors, while #741 addresses a separate bug where invalid Python syntax can cause the analyzer to raise an unhandled exception and terminate analysis.

This PR implements the bug fix and corresponding test coverage for Issue #741.