feat(repeater): suppress Adaptive Power Control while relaying

A repeater wants full, consistent TX power for relay reach, and APC's feedback
(own ACKs / own flood echoes) never fires on forwarded traffic — so leaving APC
on would relay at whatever reduced power it last trimmed to, or sit inert on a
dedicated repeater network. Force it off whenever client_repeat is on, mirroring
the power-save lock:

- apcActive() = tx_apc && !client_repeat gates every APC control site
  (sample/failure/track).
- applyApc() pins power to the tx_power_dbm ceiling; called at boot, on the
  on-device repeater toggle, and on the app's CMD_SET_RADIO_PARAMS.
- Settings "Auto pwr" shows "--" and blocks the toggle while repeating; the
  user's pref is preserved and restored when the repeater is switched off.

Also refreshes the FEATURES repeater entry (Hold-Enter reset, Errors row, schema
0x10, the radio-setting locks and status indicator).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/solo_features/tools_screen/tools_screen.md

@@ -340,7 +340,7 @@ The five flood filters are **opt-in** (default OFF, so a plain repeater is unaff
 
 **Same network vs. separate network.** With **Network = Current** (or a Custom profile set equal to your companion settings) the repeater stays on your own network — you keep messaging while relaying. With a *different* Custom profile the device moves entirely onto that network while relaying (a single radio can't be on two at once) and returns to your companion network when the repeater is switched off. The profile also re-applies after a reboot if the repeater was left on.
 
-While the repeater is on, a **»** indicator appears in the status bar (same blink convention as the auto-advert and trail markers) so you can tell it's relaying at a glance, and **Settings › Radio › Pwr save** is forced off (a repeater must listen continuously) — your power-save setting returns when you switch the repeater off.
+While the repeater is on, a **»** indicator appears in the status bar (same blink convention as the auto-advert and trail markers) so you can tell it's relaying at a glance. Two radio settings are also overridden while relaying and restored afterwards: **Settings › Radio › Pwr save** is forced off (a repeater must listen continuously) and **Auto pwr** is forced off (a repeater holds full TX power for consistent relay reach). Both show `--` in Settings while the repeater is on.
 
 Live forwarding stats — **Forwarded**, **Pool free**, **Queue** — are shown on **Tools › Diagnostics**.