Add 30 policy conformance tests for adversarial input coverage

Tests cover path traversal (relative escapes, null bytes, URL-encoded),
Unicode normalization attacks, oversized arguments, blocklisted patterns,
empty/nil policy default-deny, and cleanAndResolvePath edge cases.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: SecAI-Hub