feat: app-only settings on the device: privacy, adding contacts, advanced radio

- Settings schema gains Privacy (position in adverts, who can ask for
  status / location / sensors), Adding contacts (all or by type, max
  hops, replace oldest) and Advanced radio (path hash size, double ACK,
  listen before talk, interference threshold, RX boost, RX delay,
  airtime factor); both UIs build their rows from it
- Auto-advert carries position only when Position in adverts is on
- ui-new accordion holds 16 sections and 128 rows
- docs: settings, tools, feature matrix

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/solo/settings.md

@@ -10,10 +10,11 @@ board supports are shown.
 | **Display** | Brightness, auto-off, wake on message, the message alert (banner, corner envelope or off), lock screen, the lock clock's look and the [PIN](./lock.md), battery as icon / % / volts, time zone, clock format and seconds; on e-ink also rotation and full refresh |
 | **Sound** | Buzzer on / off / auto (quiet while the app is connected), volume, quiet hours, the melody for messages, channels and adverts |
 | **Home Pages** | Order of the home pages, and which are shown |
-| **Radio** | TX power, preset, frequency, SF / BW / CR, saved presets, Auto pwr, the scope list |
+| **Radio** | TX power, preset, frequency, SF / BW / CR, saved presets, Auto pwr, the scope list, then the advanced options (below) |
 | **System** | Device name, low-battery shutdown, GPS power saving, units, the battery curve, reboot |
 | **Keyboard** | ABC or T9 layout, the two scripts, CardKB mode |
-| **Contacts** | Show all or favourites only (DMs, channels, rooms), favourites on top, contact expiry and prune |
+| **Contacts** | Show all or favourites only (DMs, channels, rooms), favourites on top, contact expiry and prune, which heard nodes are added |
+| **Privacy** | Whether your adverts carry your position, and who may ask for your status, location and sensor readings |
 | **Messages** | Automatic resend of direct messages, the ten quick messages |
 
 A few notes:
@@ -32,6 +33,46 @@ A few notes:
   10 mV, **Reset** goes back to LiPo. The current voltage is shown, so a point
   can be set against what the battery reads.
 
+### Adding contacts
+
+A node you hear is added to your contacts according to **Auto-add**:
+
+- **All**: every node heard.
+- **By type**: only the types switched on below it (companions, repeaters,
+  rooms, sensors). With none on, nodes are added only by hand (Nearby ›
+  **Add contact**).
+
+**Up to** limits how far away an added node may be: **Direct** (heard with
+no repeater) or a number of hops. **Replace old** makes room when the list is
+full by dropping the oldest contact that isn't a favourite; without it, new
+nodes aren't added until you make room.
+
+### Privacy
+
+- **Advert pos** (Position in adverts): your adverts carry your position,
+  including the automatic ones. Off, nodes see your name but not where you
+  are. Live sharing and `{loc}` in a message still send it, because you send
+  those on purpose.
+- **Ask status / loc / sens**: who may request your telemetry: **Nobody**,
+  **Allowed** (the contacts you gave that permission, for now in the phone
+  app) or **Everyone**. Status is the battery; a request for location or
+  sensors is answered only where status is allowed too.
+
+### Advanced radio
+
+At the end of **Radio**. The defaults suit almost everyone; change them only
+if your mesh agrees on it.
+
+| Setting | Does |
+| --- | --- |
+| **Hash size** | Bytes per repeater in a message's path: 1 (the default) fits the most hops, 2 or 3 tell repeaters apart in a big mesh |
+| **Double ACK** | Sends each acknowledgement twice, for a lossy link |
+| **LBT (CAD)** | Listen before talk: waits for a quiet channel before sending |
+| **Interf.** | Treats the channel as busy when the signal is this far above the noise floor |
+| **RX boost** | The radio's boosted receive gain: hears weaker signals for a little more power (SX126x radios) |
+| **RX delay** | How long a repeated packet waits, so the best path wins; off by default |
+| **Airtime** | The pause after sending, as a multiple of the time on air |
+
 > [!NOTE]
 > **Wio Tracker L2:** one list of pages:
 >
@@ -39,7 +80,8 @@ A few notes:
 >   Power (battery, GPS, and the **Battery curve** as a chart whose points you
 >   drag), Sound (with the melody editor), Keyboard, Messages
 >   & contacts.
-> - **Connections**: Radio, Bluetooth, WiFi, GPS.
+> - **Connections**: Radio (with **Advanced** at the bottom), Privacy,
+>   Bluetooth, WiFi, GPS. Adding contacts is in Messages & contacts.
 > - **Map & data**: Map (trail, live sharing and arrival alert options),
 >   Storage.
 > - **System**: Name, Time, Units, Firmware update, About; Reboot and Power off.