feat(l2): long trails with a card copy; map follow and redraw fixes

Trail on the L2: 32768 points every 5 m, no simplification, no point
spacing setting; copied to the card every minute and restored at power-on.
The line keeps up with the position dot (incremental sync, pending point).

Map: a tap's finger jitter no longer turns follow off; the GPS button
shows when the map follows. The trail is drawn as one polyline with
breaks and off-view chunks skipped (an lv_line queued a draw task per
point).

Fewer rebuilds: conversation bubbles patched (new messages, delivery
marks), home mini-map dots reused, Nearby rows rewritten in place,
history read in runs and each file opened once.

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

examples/companion_radio/ui-lvgl/UITask.h

@@ -312,7 +312,7 @@ private:
   void buildHomeClock(lv_obj_t* box);
   void buildHomeMap(lv_obj_t* box);
   void homeFieldText(uint8_t field, char* buf, int n);
-  void homeMapFit();
+  bool homeMapFit();
   void homeMapLayout();
   void homeMapLoop();
   void refreshHome();
@@ -349,6 +349,9 @@ private:
   void buildNavLayers();
   void buildNavControls(lv_obj_t* body);
   void rebuildNavMarkers();
+  bool navTrailSync();
+  bool trailJournalTick(bool now = false);   // NavMap.h: the live trail's copy on the card
+  void trailJournalRestore();
   void layoutNav();
   void refreshNavBar();
   void navFrameTarget();
@@ -534,6 +537,8 @@ private:
   lv_obj_t* _map_marks = nullptr;
   lv_obj_t* _map_me = nullptr;
   lv_obj_t* _map_zoom_lbl = nullptr;
+  lv_obj_t* _map_center_btn = nullptr;   // accent while the map follows you
+  uint32_t  _next_follow_ms = 0;
   lv_obj_t* _map_hint = nullptr;
   lv_obj_t* _map_dl_pill = nullptr;     // download progress over the map
   lv_obj_t* _dl_overlay = nullptr;      // download popup