feat(repeater): politeness controls, dedicated radio profile, and diagnostics

Settings > Radio gains a repeater toggle, 16 community-suggested radio
presets plus manual Freq/SF/BW/CR tuning (digit-by-digit Freq editor),
4 persisted user preset slots, and the packet pool bumped 16->32 so
queued retransmits stop starving incoming-packet allocation while
relaying.

Four opt-in politeness knobs (skip-advert, max-hops, yield, min-SNR),
all flood-only and off by default, plus overhear suppression that
cancels a queued retransmit if a peer relays the same packet first.
Adaptive Power Control is suppressed while relaying (pins TX power to
the ceiling) and duty-cycle RX is forced off, since a repeater needs
to hear and relay at consistent power.

A dedicated Tools > Repeater screen consolidates the toggle, the
politeness knobs, and live forwarding stats, plus an optional "Custom"
radio profile — a dedicated frequency/SF/BW/CR for relaying, separate
from the companion's own network, band-matched to the companion
frequency by default and used everywhere a radio change can happen
(boot, on-device toggle, app-driven CMD_SET_RADIO_PARAMS, Settings
radio edits) so the device never silently falls back to the wrong
params mid-relay.

Diagnostics gains the actually-forwarded packet count, real heap-free
via mallinfo(), a reset-counters popup, and hardened loop-detect
bounds. Also: a frequency-floor fix and a float-equality preset-match
fix in the repeater profile logic, deduped BW-table/valCol/profile-
seeding helpers shared between Settings and the Repeater screen, and
a build.sh fix tolerating control characters in `pio project config`'s
JSON dump.

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

examples/companion_radio/ui-new/UITask.h

@@ -80,6 +80,7 @@ class UITask : public AbstractUITask {
   UIScreen* trail_screen;
   UIScreen* compass_screen;
   UIScreen* diag_screen;
+  UIScreen* repeater_screen;
   UIScreen* curr;
   CayenneLPP _dash_lpp;
   TrailStore _trail;
@@ -154,6 +155,7 @@ public:
   void gotoTrailScreen();
   void gotoCompassScreen();
   void gotoDiagnosticsScreen();
+  void gotoRepeaterScreen();
   TrailStore& trail() { return _trail; }
   WaypointStore& waypoints() { return _waypoints; }
   // Shared on-screen keyboard — only one screen drives it at a time.
@@ -260,6 +262,7 @@ public:
   void applyTxPower();
   void applyPowerSave();   // hardware duty-cycle RX on/off from prefs
   void applyApc();         // Adaptive Power Control on/off from prefs
+  void applyRadioParams(); // freq/bw/sf/cr from prefs (radio preset change)
   void applyFont();
   void applyRotation();
   void applyFullRefreshInterval();