build: prepare QuantumD v0.7.4 alpha

[WindDAnalytics]

Summary

Prepares QuantumD 0.7.4a0 from the hardened public-alpha main branch.

This release carries forward the permanent public-alpha acceptance contract:

• build from tracked source
• install and execute a real wheel
• resolve QuantumD from site-packages
• deny unsigned governed execution
• run local onboarding without cloud trust
• resist poisoned IBM and GCP credentials
• prohibit hardware authorization
• validate QVERIFY and QEXEC evidence contracts
• independently verify the evidence chain offline
• preserve repository state

Validation

• 32 tests passed
• Source and installed package versions matched 0.7.4a0
• Wheel and source distribution built successfully
• Both distributions passed twine check
• Required packaged files were confirmed
• Public-alpha wheel acceptance passed
• Unsigned governed execution failed closed
• Local quickstart passed
• All 10 independent chain checks passed
• Strict documentation build passed

Release process

After merge, an immutable v0.7.4-alpha tag will trigger the protected TestPyPI release workflow using GitHub OIDC, GCP Workload Identity Federation, and KMS-attested release validation.