Two diagnosability gaps found by exercising the docker-update vertical
live with a real agent, each of which turns 'approved action cannot
execute' into a dead end with no visible cause:
- The durable operation-receipt store failing to open (e.g. unwritable
state dir) silently registered the agent with receipt version 0; the
only symptom was a server-side claim that the agent was too old. The
agent now logs the real cause and state dir loudly at startup.
- The server readiness copy asserted 'older agent version' for any
receipt-version mismatch. It now names both causes (old version or
unavailable state directory) and points at the agent logs.
(The related docker collect-cycle watchdog landed separately in
a0f75b1bb with a hung-daemon reproducer.)
Contract-Neutral: agent-side diagnosability: receipt-store failure warning + honest readiness copy; no public contract delta
rcourtman
331758f32b