Bug: multi_arch_oracles.py crashes with NameError — hmac used before import

[508704820]

Bug: hmac module used before import, causing NameError crash

Severity: Medium (Crash)

File: src/mutator_oracle/multi_arch_oracles.py, generate_mutation_seed() (lines 288-292)

Description:
Line 288 calls hmac.new() but hmac is only imported inside the demo function on line 481 (import hmac # Import for ring signature). When generate_mutation_seed() is called in production, it crashes with NameError: name 'hmac' is not defined.

The fallback on line 292 (if 'hmac' in dir()) never executes because the NameError is thrown on line 288 first.

Reproduction:

# Call generate_mutation_seed() → NameError: name 'hmac' is not defined

Impact:

• Multi-architecture oracle seed generation crashes in production
• Ring signature never works — always falls through to broken code path
• If somehow fixed, the fallback sha256(final_seed) is not a proper HMAC ring signature

Expected Fix:

• Import hmac at module level (with other imports)
• Remove the if 'hmac' in dir() fallback — it's dead code that masks the real issue