fix: verify adaptive selection decision digest

[Pigbibi]

Summary

• require and independently recompute the QPK canonical decision digest before M1 accepts a Shadow source
• retain closed fields, shadow-only authority, no-order state, and zero proposed-weight validation
• reject legacy records without a digest rather than manufacturing audit data

Safety

• no platform, runtime, dispatch, credential, or UI action permission is changed
• an invalid source cannot overwrite a valid M1 display record

Validation

• node tests/strategy_switch_worker_validation.mjs passed locally
• node syntax and diff checks passed
• GitHub CI will run JS, Python, and workflow checks