feat: discover routes from OpenAPI spec files when Noir fallback is used

[google-labs-jules]

What:
Adds an OpenAPI fallback extractor that scans JSON, YAML, and YML files for OpenAPI/Swagger definitions. When Noir is absent or falls back, this new logic parses these spec files and extracts HTTP methods and routes (either via direct JSON parsing or line-by-line regex parsing for YAML).

Why:
VAmPI tests were failing because endpoints didn't match the required 10 endpoints due to missing Noir OpenAPI handling. The websec proof score regressed to 8/10 as a result.

Risk:
Low. The fallback is wrapped in try/except blocks to prevent crashes on malformed files and is gated behind _fallback processing.

Tests:
Includes two new regression tests in tests/test_pentest_regressions.py to assert extraction works for both JSON and YAML OpenAPI files. Also fixes a test regression in test_hooks.py by enforcing local git hooks usage during the test.

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PR created automatically by Jules for task 12011950927894770504 started by @raccioly

[google-labs-jules]

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