feat(gps): use HDOP for !gps fix readiness, satellite count as fallback

Satellite count alone is a poor proxy for fix quality -- few satellites
in good geometry can beat many in poor geometry. LocationProvider now
exposes getHDOP() (default -1 = unsupported); MicroNMEA implements it.
isLocFixReady() prefers HDOP <= 2.0 when available, falling back to the
old >=8 satellite threshold for providers that don't report it (e.g.
RAK12500/u-blox).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/solo_features/tools_screen/tools_screen.md

@@ -451,7 +451,7 @@ A separate **Actions** toggle, nested under Commands (Commands must be ON for Ac
 | ----------------- | -------------------------------------------------------------------- |
 | `!buzz [seconds]` | Sounds the buzzer as a find-me signal — default 5s, capped at 30s. Sounds even if the buzzer is muted in Settings (that's the point of a find-me signal). |
 | `!gps on` / `!gps off` | Enables/disables GPS, same effect as the Home page's GPS toggle.  |
-| `!gps fix`        | Single-shot location: turns GPS on if it wasn't already, waits for a stabilised fix (≥8 satellites, averaged over 10s), sends the position, then restores GPS to whatever state it was in before. Replies in two parts — an immediate `GPS: acquiring fix...` ack, then the position (or `GPS: no fix (timeout)` / a partial fix) as a follow-up message up to 90s later. Only one `!gps fix` can be in flight at a time; a second one gets `GPS: fix already pending`. |
+| `!gps fix`        | Single-shot location: turns GPS on if it wasn't already, waits for a stabilised fix (HDOP ≤ 2.0, or ≥8 satellites on GPS hardware that doesn't report HDOP, averaged over 10s), sends the position, then restores GPS to whatever state it was in before. Replies in two parts — an immediate `GPS: acquiring fix...` ack, then the position (or `GPS: no fix (timeout)` / a partial fix) as a follow-up message up to 90s later. Only one `!gps fix` can be in flight at a time; a second one gets `GPS: fix already pending`. |
 | `!advert`         | Sends an advert immediately, same as the Home page's manual advert action. |
 
 Actions combine with Commands and each other in one message the same way — `!batt !gps on` answers with `4.10V | GPS: on` in a single reply. With Actions OFF for a target, `!buzz`/`!gps`/`!gps fix`/`!advert` are silently ignored (no reply, no effect) exactly like any other unrecognised command, and `!help`'s reply doesn't mention them.

examples/companion_radio/MyMesh.h

@@ -338,6 +338,7 @@ private:
   void tickLocFix();     // ticked every loop() while _loc_fix.active
   void startLocFix(uint8_t dest_type, const uint8_t* pub_key, uint8_t channel_idx);
   void sendLocFixResult(const char* msg);
+  static bool isLocFixReady(LocationProvider* loc);   // HDOP if the provider has it, else satellite count
   bool botTriggerMatches(const char* trigger, const char* body, bool allow_wildcard) const;
   bool botInQuietHours() const;               // true when auto-replies should stay silent
   bool botDmAllowed(const uint8_t* pubkey);   // per-contact DM throttle: ok to reply?
@@ -442,7 +443,11 @@ private:
   // !gps fix state -- one global slot (one physical GPS): botCommandReply()
   // rejects a second request outright while one is active, so this never
   // needs to be an array. See tickLocFix()/startLocFix() in MyMeshBot.h.
-  static const int LOCFIX_MIN_SATS = 8;            // readiness threshold
+  // Readiness: HDOP (tenths, lower=better) when the provider exposes it --
+  // 20 == HDOP 2.0, the usual "good fix" cutoff -- else satellite count as a
+  // cruder fallback (see LocationProvider::getHDOP()'s -1 = "not available").
+  static const int LOCFIX_MAX_HDOP = 20;
+  static const int LOCFIX_MIN_SATS = 8;            // readiness threshold (HDOP-less fallback)
   static const uint32_t LOCFIX_AVERAGE_MS = 10000;  // once ready, keep averaging this long
   static const uint32_t LOCFIX_TIMEOUT_MS = 90000;  // hard stop covering both phases
   enum { LOCFIX_DEST_CONTACT = 0, LOCFIX_DEST_CHANNEL = 1 };  // CONTACT covers DM and room alike (both reply via sendMessage)

examples/companion_radio/MyMeshBot.h

@@ -522,19 +522,27 @@ void MyMesh::startLocFix(uint8_t dest_type, const uint8_t* pub_key, uint8_t chan
 }
 
 // !gps fix state machine, ticked every MyMesh::loop() while _loc_fix.active.
-// Phase 1 (acquire): wait for a valid fix with at least LOCFIX_MIN_SATS
+// Phase 1 (acquire): wait for a valid fix good enough to trust -- HDOP (fix
-// satellites. Phase 2 (average): once that's first met, keep summing
+// geometry) when the provider exposes it, satellite count as a cruder
-// node_lat/node_lon for LOCFIX_AVERAGE_MS more -- only on ticks where the
+// fallback when it doesn't (see isLocFixReady()). Phase 2 (average): once
-// threshold still holds, so a momentary drop below LOCFIX_MIN_SATS just skips
+// that's first met, keep summing node_lat/node_lon for LOCFIX_AVERAGE_MS more
-// a sample instead of aborting the whole wait. A hard LOCFIX_TIMEOUT_MS
+// -- only on ticks where the threshold still holds, so a momentary dip just
+// skips a sample instead of aborting the whole wait. A hard LOCFIX_TIMEOUT_MS
 // deadline covers both phases; on timeout with zero samples collected the
 // result is a plain failure (no stale-cache fallback -- a cached node_lat/lon
 // from long before this request would be actively misleading here).
+bool MyMesh::isLocFixReady(LocationProvider* loc) {
+  if (!loc || !loc->isValid()) return false;
+  long hdop = loc->getHDOP();
+  if (hdop >= 0) return hdop <= LOCFIX_MAX_HDOP;    // preferred: real fix-quality signal
+  return loc->satellitesCount() >= LOCFIX_MIN_SATS; // provider has no HDOP -- cruder fallback
+}
+
 void MyMesh::tickLocFix() {
   if (!_loc_fix.active) return;
 
   LocationProvider* loc = sensors.getLocationProvider();
-  bool ready = loc && loc->isValid() && loc->satellitesCount() >= LOCFIX_MIN_SATS;
+  bool ready = isLocFixReady(loc);
 
   if (_loc_fix.averaging_until_ms == 0 && ready) {
     _loc_fix.averaging_until_ms = futureMillis(LOCFIX_AVERAGE_MS);

release-notes.md

@@ -4,7 +4,7 @@
 
 - **Auto-Reply Bot is renamed to Remote Bot.** It's grown beyond auto-replies into remote device control (Actions, below), so the Tools screen entry and docs now say "Remote Bot" — same screen, same settings, nothing to reconfigure.
 - **Remote Bot gains Actions: `!buzz`, `!gps`, `!advert`.** A new **Actions** toggle (per target — Direct/Channel/Room, nested under each target's existing **Commands** toggle) enables three commands that change the device's own behaviour instead of just reporting on it: `!buzz [seconds]` sounds the buzzer as a find-me signal (default 5s, capped at 30s, sounds even if the buzzer is muted), `!gps on`/`!gps off` toggles GPS, and `!advert` sends an immediate advert. Off by default; combines with the existing query commands in one message the same way (`!batt !gps on` → `4.10V | GPS: on`).
-- **`!gps fix` — single-shot GPS location, no need to leave GPS running.** Turns GPS on (if it wasn't already), waits for a stabilised fix (≥8 satellites, then averages for 10s), sends the position, and restores GPS to whatever state it was in before — up to a 90s timeout, after which it reports a partial fix (if it got at least some samples) or failure. Replies in two parts: an immediate "acquiring fix..." ack, then the actual position as a follow-up message once ready. Only one fix request can be in flight at a time (a second one gets "fix already pending"); same Actions toggle as `!buzz`/`!gps`/`!advert`.
+- **`!gps fix` — single-shot GPS location, no need to leave GPS running.** Turns GPS on (if it wasn't already), waits for a stabilised fix (HDOP ≤ 2.0 — falls back to ≥8 satellites on GPS hardware that doesn't report HDOP — then averages for 10s), sends the position, and restores GPS to whatever state it was in before — up to a 90s timeout, after which it reports a partial fix (if it got at least some samples) or failure. Replies in two parts: an immediate "acquiring fix..." ack, then the actual position as a follow-up message once ready. Only one fix request can be in flight at a time (a second one gets "fix already pending"); same Actions toggle as `!buzz`/`!gps`/`!advert`.
 - **Bot Trigger fields accept multiple phrases.** Pack several trigger words into one Trigger field, comma-separated (`hi,hello there,yo`) — matching any one of them fires the reply, same as before for a single phrase.
 - **Remote Bot Actions gain `!gpio1`..`!gpio4`** (Wio Tracker L1 only — 4 otherwise-unused pins). Each pin is independently set to Off/Input/Output (GPIO1/GPIO2 also offer Analog) from a new **Tools › GPIO** screen; `!gpio1 on`/`!gpio1 off` drives an Output pin remotely, a bare `!gpio1` reports the current mode and reading (including a millivolt value in Analog mode). Gated by the same per-target Actions toggle as `!buzz`/`!gps`/`!advert`.
 - **Optional CardKB support (Wio Tracker L1, Grove I2C) — full keyboard-only navigation.** Plug an M5Stack CardKB into the Grove connector and it's auto-detected at boot — no setting to flip. Typing goes straight into the message/name field instead of navigating the on-screen keyboard grid; arrows and Esc work as expected everywhere else too (including inside the placeholder and accent popups). Enter acts like the physical centre button (advances the on-screen grid selection) rather than submitting, so **Fn+Enter** sends the message/confirms the field from anywhere, **Fn+`<letter>`** opens that letter's accent popup directly (no arrow-hunting needed — handy for Polish/Czech/etc. diacritics), and **Fn+Tab** opens the Hold-Enter equivalent (Shift-lock, clear field) for whatever's selected; plain **Tab** still opens the Hold-Enter context menu everywhere else (message reply/navigate, Bot/Admin/Repeater menus, …).

src/helpers/sensors/LocationProvider.h

@@ -14,6 +14,12 @@ public:
     virtual long getLongitude() = 0;
     virtual long getAltitude() = 0;
     virtual long satellitesCount() = 0;
+    // Horizontal Dilution of Precision, in tenths (11 == HDOP 1.1) -- lower is
+    // better, and a much more direct read on fix quality than satellite count
+    // alone (few satellites in good geometry can beat many in poor geometry).
+    // -1 means this provider doesn't expose it; callers fall back to
+    // satellitesCount() in that case.
+    virtual long getHDOP() { return -1; }
     virtual bool isValid() = 0;
     virtual long getTimestamp() = 0;
     virtual void sendSentence(const char * sentence);

src/helpers/sensors/MicroNMEALocationProvider.h

@@ -120,6 +120,7 @@ public :
         return alt;
     }
     long satellitesCount() override { return nmea.getNumSatellites(); }
+    long getHDOP() override { return nmea.getHDOP(); }
     bool isValid() override { return nmea.isValid(); }
 
     long getTimestamp() override {