feat(companion): live location sharing, Locator geofencing, trail auto-pause

Squash merge of feat/location-beacon-alerts-autopause (v1.21).

Features:
- Live Location Sharing — broadcast position as movement-gated [LOC]
  messages to a channel or contact; live shares show as map pins with
  distance/bearing in Nearby Nodes and a status-bar indicator. [LOC] is
  parsed in DMs, channel messages and room messages; DM shares name the
  sender.
- Locator (geofence) — arm a geofence around a saved waypoint or a person
  (live [LOC] or last-known position), alert on arrive/leave or near/far,
  with an optional homing beeper (gated to arrive/both modes). Arm from
  Tools > Locator, Nearby Nodes, or Waypoints; target picker lists
  favourites first, clearable via a "None" entry. Active target is drawn
  as a flag on the map.
- One active target shared across Locator / Navigate / Map via a single
  resolver (resolvePersonPos / activeTargetPos) that prefers a live
  [LOC] share over the last-advertised GPS fix.
- Follow live contacts — Navigate to a live-sharing contact follows them
  as they move and adds an ETA line; quick-share your own position from
  the Map.
- Map & status-bar upgrades — home mini-map gets a north marker, scale
  tick, and a connected trail line (was disconnected dots); status line
  shows tracked-node count, an arrow + distance to the active Locator/Nav
  target (falling back to the nearest live-tracked contact); GPS fix icon
  in the top status bar, shown only on GPS boards with GPS enabled.
- Trail auto-pause — recording freezes on stops (banking elapsed time,
  breaking the map line across the idle gap) and resumes on movement
  without ending the session.
- Streaming trail simplification — GPS points are simplified in-stream
  via a fixed-corridor (Reumann-Witkam) pass tuned for fidelity: straight
  runs collapse to their endpoints, curves stay bounded to the Min-dist
  tolerance, so the 512-point buffer covers a far longer route than a
  flat point budget would suggest.
- Collapsible Tools (Location / Comms / System sections, fold-in-place
  like Settings) and page-indicator icons on the home carousel.
- Waypoint coordinate editor — add a waypoint by scroll-editing lat/lon
  digit by digit.

Fixes:
- Critical: low-heap hang and contact loss on RAM-tight builds. Halved
  message-history scrollback rings (recovering ~14 KB free heap) and
  made contacts/channels/prefs persistence atomic (temp file + rename),
  so an interrupted save can no longer corrupt or wipe the store.
- Serial.write() bounded so a stalled USB host can't hang the device.
- Nearby Nodes: live [LOC] senders respect the type filter, sort by
  shared position, and the list refreshes so live shares bubble up.
- Map: live contacts are labelled before waypoints.
- GPS status icon hidden when GPS is off in Settings.
- Splash screen no longer truncates a pre-release tag's own dash (e.g.
  v1.21-rc1) when stripping the build's commit-hash suffix.
- Null-guarded the Locator target picker; clamped loc-share channel
  index on load.

Under the hood:
- -Os size optimisation on the e-ink and GAT562 30S solo envs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

examples/companion_radio/ui-new/icons.h

@@ -165,6 +165,127 @@ MINI_ICON(ICON_REPEATER, 6,   // » double chevron — relaying/forwarding (repe
   packRow(".#..#."),
   packRow("#..#.."));
 
+MINI_ICON(ICON_GPS, 5,   // reticle — GPS fix status (boxed = fix, plain = searching)
+  packRow(".###."),
+  packRow("#...#"),
+  packRow("#.#.#"),
+  packRow("#...#"),
+  packRow(".###."));
+
+// Tools-menu glyphs (auto-reply bot, ringtone editor, diagnostics, system).
+MINI_ICON(ICON_BOT, 5,   // robot head: antenna + eyes + grille (auto-reply bot)
+  packRow("..#.."),
+  packRow("#####"),
+  packRow("#.#.#"),
+  packRow("#####"),
+  packRow("#.#.#"),
+  packRow("#####"));
+MINI_ICON(ICON_NOTE, 5,   // ♪ quaver — ringtone editor
+  packRow("...##"),
+  packRow("...##"),
+  packRow("...#."),
+  packRow("...#."),
+  packRow("...#."),
+  packRow("####."),
+  packRow("####."));
+MINI_ICON(ICON_CHART, 5,   // ascending bars — diagnostics / stats
+  packRow("....#"),
+  packRow("..#.#"),
+  packRow("..#.#"),
+  packRow("#.#.#"),
+  packRow("#.#.#"),
+  packRow("#####"));
+MINI_ICON(ICON_GEAR, 7,   // ⚙ cog with hub hole — system
+  packRow("..#.#.."),
+  packRow(".#####."),
+  packRow("#######"),
+  packRow(".##.##."),
+  packRow("#######"),
+  packRow(".#####."),
+  packRow("..#.#.."));
+
+// Home-carousel page glyphs — a uniform 5x5 set, deliberately smaller than the
+// menu/status icons above, used in place of the page-indicator dots. One per
+// HomePage; see UITask HomeScreen::pageIcon().
+MINI_ICON(ICON_PG_CLOCK, 5,      // clock face + hands
+  packRow(".###."),
+  packRow("#.#.#"),
+  packRow("#.###"),
+  packRow("#...#"),
+  packRow(".###."));
+MINI_ICON(ICON_PG_STAR, 5,       // favourites
+  packRow("..#.."),
+  packRow("#####"),
+  packRow(".###."),
+  packRow("##.##"),
+  packRow("#...#"));
+MINI_ICON(ICON_PG_RECENT, 5,     // stacked lines — recent list
+  packRow("#####"),
+  packRow("....."),
+  packRow("#####"),
+  packRow("....."),
+  packRow("#####"));
+MINI_ICON(ICON_PG_RADIO, 5,      // antenna tower — radio params
+  packRow("..#.."),
+  packRow(".###."),
+  packRow("..#.."),
+  packRow(".#.#."),
+  packRow("#...#"));
+MINI_ICON(ICON_PG_BT, 5,         // bluetooth (compact)
+  packRow("..#.."),
+  packRow("#.##."),
+  packRow(".###."),
+  packRow("#.##."),
+  packRow("..#.."));
+MINI_ICON(ICON_PG_ADVERT, 5,     // mast + radiating waves — advert
+  packRow("#...#"),
+  packRow(".#.#."),
+  packRow("..#.."),
+  packRow("..#.."),
+  packRow("..#.."));
+MINI_ICON(ICON_PG_GPS, 5,        // location pin — GPS
+  packRow(".###."),
+  packRow("#.#.#"),
+  packRow("#.#.#"),
+  packRow(".#.#."),
+  packRow("..#.."));
+MINI_ICON(ICON_PG_SENSORS, 5,    // thermometer/gauge — sensors
+  packRow("..#.."),
+  packRow(".#.#."),
+  packRow(".#.#."),
+  packRow(".###."),
+  packRow(".###."));
+MINI_ICON(ICON_PG_SETTINGS, 5,   // small cog — settings
+  packRow(".#.#."),
+  packRow("#####"),
+  packRow("##.##"),
+  packRow("#####"),
+  packRow(".#.#."));
+MINI_ICON(ICON_PG_MAP, 5,        // folded map — map page
+  packRow("#####"),
+  packRow("#.#.#"),
+  packRow("#.#.#"),
+  packRow("#.#.#"),
+  packRow("#####"));
+MINI_ICON(ICON_PG_TOOLS, 5,      // wrench (open jaw + handle) — tools
+  packRow(".#.#."),
+  packRow(".###."),
+  packRow("..#.."),
+  packRow("..#.."),
+  packRow("..#.."));
+MINI_ICON(ICON_PG_MSG, 5,        // speech bubble — quick messages
+  packRow("#####"),
+  packRow("#...#"),
+  packRow("#...#"),
+  packRow("#####"),
+  packRow(".#..."));
+MINI_ICON(ICON_PG_POWER, 5,      // power symbol — shutdown
+  packRow("..#.."),
+  packRow("#.#.#"),
+  packRow("#...#"),
+  packRow("#...#"),
+  packRow(".###."));
+
 // Trail-map markers — centred on a point (see miniIconDrawCentered) rather
 // than anchored to a text line.
 MINI_ICON(ICON_MAP_DOT, 3,        // ● filled trail point
@@ -193,6 +314,12 @@ MINI_ICON(ICON_MAP_CURRENT, 5,    // ✕ live position / last trail point
   packRow("..#.."),
   packRow(".#.#."),
   packRow("#...#"));
+MINI_ICON(ICON_MAP_CONTACT, 5,    // ◆ filled diamond — a live-tracked contact ([LOC] share)
+  packRow("..#.."),
+  packRow(".###."),
+  packRow("#####"),
+  packRow(".###."),
+  packRow("..#.."));
 MINI_ICON(ICON_MAP_NORTH, 5,      // "N" with a peaked roof — compass north marker
   packRow("..#.."),
   packRow(".###."),
@@ -201,6 +328,18 @@ MINI_ICON(ICON_MAP_NORTH, 5,      // "N" with a peaked roof — compass north ma
   packRow("#.#.#"),
   packRow("#..##"),
   packRow("#...#"));
+MINI_ICON(ICON_MAP_ARROW, 5,      // → distance-to-nearest-tracked-contact indicator
+  packRow("..#.."),
+  packRow("...#."),
+  packRow("#####"),
+  packRow("...#."),
+  packRow("..#.."));
+MINI_ICON(ICON_MAP_TARGET, 5,     // ⚑ flag on a pole — the active Locator/Nav target
+  packRow("####."),
+  packRow("#..#."),
+  packRow("####."),
+  packRow("#...."),
+  packRow("#...."));
 
 // Keyboard special-key glyphs.
 MINI_ICON(ICON_SHIFT, 7,   // ⇧  caps