docs: document repeater politeness knobs and Diagnostics screen

- settings_screen: full Radio section (Preset/Freq/SF/BW/CR/Repeater were
  undocumented), plus the five flood-only politeness sub-items.
- tools_screen: new Diagnostics section (per-type counters, heap/stack, radio,
  pool/queue, Forwarded, reset popup).
- README + FEATURES: mention diagnostics; FEATURES gets a full repeater entry.

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

FEATURES.md

@@ -441,6 +441,50 @@ Sequencing: hardware duty-cycle RX and APC are both done and in field test on
 `feat/power-saving`; see the status block at the top of this entry for what's
 left (PPK2 current measurement, multi-hop APC gating).
 
+### ✅ Companion repeater + politeness knobs + diagnostics
+
+On-device repeater for the Solo companion, scoped to the SX1262 boards (Wio
+Tracker L1 OLED/e-ink, GAT562 30S). All on `feature/companion-repeater-presets`.
+
+- **Repeater toggle** (`client_repeat`, Settings › Radio) — the companion relays
+  flood/direct traffic on its **current** frequency (no dedicated band), still
+  working as a normal companion. `MyMesh::allowPacketForward` gates it; loop
+  detection (`isRepeatLooped`, ported from `simple_repeater`) and an advert
+  flood-depth cap are always applied. Packet pool bumped 16→32 to match the
+  repeater workload (a too-small pool starved channel/DM reception once relaying
+  queued retransmits).
+- **Politeness knobs** (all opt-in, default off, flood-only — a direct route's
+  named next hop is never dropped). Shown under Radio only while the repeater is
+  on:
+  - **Skip advert** — don't re-flood adverts (highest-volume flood).
+  - **Max hops** — drop a flood past N hops.
+  - **Yield** — scale the retransmit delay for *forwarded* floods only
+    (`getRetransmitDelay`); own sends pass their own delay to `sendFlood`, so the
+    companion's own traffic is never slowed. Widens the overhear window.
+  - **Min SNR** — drop a flood copy below a dB threshold (`-128` sentinel = off,
+    so an upgraded prefs file can't read as "filter at 0 dB").
+  - **Suppress dup** — overhear cancel: a received flood whose hash matches a
+    queued retransmit cancels our copy (`Dispatcher::suppressQueuedDuplicate`,
+    `wantsOverhearSuppress` hook). MeshCore had no overhear-cancel before — the
+    unused `removeOutboundByIdx`/`getOutboundByIdx` finally have a caller. Packet
+    hash ignores the path for non-TRACE, so our copy and the peer's relayed copy
+    hash equal. Pairs with Yield (longer delay → wider window to hear a peer).
+- **Diagnostics screen** (Tools › Diagnostics) — single read-only page: per-type
+  RX/TX counters (generic `Dispatcher::n_recv_by_type`/`n_sent_by_type`), uptime,
+  heap + stack (new `DeviceDiag` helper, nRF52 linker-symbol/`sbrk` heap +
+  FreeRTOS stack high-water), noise floor, RSSI/SNR, pool free, outbound queue,
+  and **Forwarded** (`Mesh::n_forwarded` — actual retransmits; backed out on
+  overhear cancel so it reflects what hits the air). Enter opens a confirm popup
+  to reset the cumulative counters (`resetStats` made virtual; `Mesh` override
+  also clears `n_forwarded`).
+- Prefs persisted behind schema sentinels `0xC0DE000E` (four knobs) then
+  `0xC0DE000F` (suppress-dup), with stray-byte clamps for upgraders.
+- **Open question:** the app-side dedicated-band gate in `CMD_SET_RADIO_PARAMS`
+  was commented out (not deleted) to match the on-device toggle's any-frequency
+  behaviour — undecided whether that gate was UX-only or regulatory.
+- **Not done:** live two-device mesh verification (A→repeater→C); counters make
+  it observable but don't replace the field test.
+
 ### SOS broadcast
 
 Configurable in Settings › System › SOS: