Field session: after a recovery teardown the heap settles at ~72 KB --
below the 100 KB start floor -- and never recovers on its own (the
defrag silent-restart only fires when a build FAILS, and builds succeed
now). BT stayed paused forever, the menu toggle claimed ON, and toggling
off/on changed nothing.
- Menu label tells the truth: ON / PAUSED (enabled but stack down) / OFF
(new STR_STATE_PAUSED string)
- Toggling BT on below the heap floor silent-restarts into the current
book: the fresh boot's ~118 KB passes the gate and BT auto-starts on
resume. Explicit user intent is the right trigger for the defrag.
- Hoist the floor to bleinput::kStartMinFreeHeap, shared by the
lifecycle gate and the toggle