Verify EQ writes with readback evidence

[NiceDayZc]

What changed

• adds protocol-aware EQ state extraction and per-band read-back verification
• captures the state before writing, checks the write response, reads again, and compares expected/actual/delta values
• distinguishes CHANGED + VERIFIED, ALREADY MATCHED + VERIFIED, mismatch, missing/rejected acknowledgement, undecodable read-back, and transport failure
• automatically opens Activity and logs a transaction ID, hashed target, PID/profile/route, every TX/RX frame, decoded evidence, timing, and partial-write failure stage
• fixes Protocol 4 parametric read-back offsets and sample-rate decoding
• persists complete verification evidence in the privacy-aware JSONL audit record

Hardware evidence

JBL Charge 6 PID 20e3, firmware 3.0.7.1, was tested with a controlled state transition. Band 7 changed from 0.0 to +0.5 dB, returned one write response, and read back with zero delta across all seven bands. It was then restored to 0.0, returned one response, and read back with zero delta again.

Validation

• 53 tests passed
• full-package branch coverage: 71.98%
• Ruff and formatting passed
• mypy passed
• Bandit passed
• pip-audit found no known vulnerabilities
• wheel/sdist build and Twine checks passed