MEM-005 | Add EEPROM ring buffer storage

[wxkim]

Problem statement: what's wrong with it?

• Continuous writes can overwrite useful data unpredictably.

Ideal situation: describe the solution you'd like.

• Use ring buffer with head/tail management for log records.

Proposed solutions: describe alternatives you've considered

• Linear append + erase vs ring buffer (ring preferred).

Additional context

• Supports continuous operation with bounded storage.