Python: Integrate auto-formatting into template engine

[knutwannheden]

Summary

• Add auto_format() and maybe_auto_format() helper functions to the Python format module, mirroring the JS template system's maybeAutoFormat pattern
• Call maybe_auto_format in _apply_coordinates after template application so templated AST nodes get properly formatted (operator spacing, indentation, etc.)
• The formatter resolves styles from the CompilationUnit in the cursor ancestry and formats only the templated subtree, gracefully skipping when no CU context is available
• Fix comparator element access to use unwrapped elements directly

Test plan

• rewrite_run integration test: template with bad operator spacing ({expr}+2) produces correct output (a + 2)
• rewrite_run integration test: template with missing comma space (print('prefix',{msg})) produces correct output (print('prefix', 'hello'))
• rewrite_run integration test: formatting preserves correct indentation in deeply nested scope (class > def > if)
• Unit test: maybe_auto_format identity guard (same object → skip formatting)
• Unit test: auto_format without cursor returns tree unchanged
• Unit test: _apply_coordinates without CU context does not crash
• All 158 existing template + format tests pass with no regressions

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