MEM-004 | Add periodic EEPROM status/error logging

[wxkim]

Problem statement: what's wrong with it?

• No periodic persistence of status/fault snapshots.

Ideal situation: describe the solution you'd like.

• Log selected status/error fields at fixed interval.

Proposed solutions: describe alternatives you've considered

• Event-only logs vs periodic snapshots (periodic preferred for MVP).

Additional context

• Keep payload small to control wear.