#622 Cython optimization: secure_logging.py SensitiveDataFilter.filter()

**Target:** engine/utils/secure_logging.py - SensitiveDataFilter.filter() method **Expected Gain:** 25-40% **Bottleneck Analysis:** - Called on EVERY log record (147+ times per workflow in orchestrator + operators) - Nested loop: 8 regex patterns x N args x string length - Complexity: O(num_args x num_patterns x strlen) **Cython Strategy:** - Convert PATTERNS to C-level compiled regex - Use typed cdef for inner loops - Eliminate Python object overhead in pattern matching - Pre-allocate filtered_args list with known size **Priority:** HIGH - affects all logging throughout the engine Tags: cython, performance