24-hour stability soak (PAGER_SPEC.md §9 #7)

[juergen-kc]

PAGER_SPEC.md §9 criterion 7 — "no resets or OOMs over a 24-hour continuous-use session" — has not been run.

Things to watch for during the soak:

• Heap fragmentation in pager::store::stats writes (counters write through immediately; many small NVS writes over 24 h).
• NimBLE bond store growth on repeated unpair/repair cycles.
• LVGL animation timer drift over a long uptime.
• USB-CDC stability under host sleep/wake cycles.

Tracked in BACKLOG.md.