feat(nodes): on-device add/delete/favourite + circular filter tabs, rename to "Nodes"

Turn Nearby Nodes into the single node hub and make its navigation legible.

Node management (no phone app needed):
- MyMesh gains addDiscoveredContact() and deleteContactByKey(); CMD_REMOVE_CONTACT
  now reuses deleteContactByKey() (one delete path: contact + blob + room password
  + UI cleanup + lazy write).
- Action menu (Hold Enter) gains Add contact (a new scanned node), Favourite /
  Unfavourite (pin to the first free dial slot), and Delete contact (confirm first,
  defaults to Cancel). Actions are offered contextually per row.
- A pinned contact shows a star in the list row, next to any live-share diamond.

Absorb passively-heard adverts: refreshStored() folds getRecentlyHeard() nodes that
aren't already listed as name+age rows (All filter only — AdvertPath has no type),
so "recently heard" no longer needs its own page.

Legible filter navigation: the filter (LEFT/RIGHT) is now a visible tab strip — the
active filter is a centred inverted pill, neighbours fan out and wrap around
(circular, first<->last). Only whole tabs are drawn so labels never wrap a line.

Rename Tools > "Nearby Nodes" to "Nodes".

Both solo envs build green.

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

examples/companion_radio/ui-new/ToolsScreen.h

@@ -111,7 +111,7 @@ public:
 };
 
 const ToolsScreen::Tool ToolsScreen::LOCATION_TOOLS[] = {
-  { "Nearby Nodes", &ICON_MAP_CONTACT,  ACT_NEARBY },
+  { "Nodes", &ICON_MAP_CONTACT,  ACT_NEARBY },
   { "Live Share",   &ICON_GPS,          ACT_LIVESHARE },
   { "Trail",        &ICON_TRAIL,        ACT_TRAIL },
   { "Locator",    &ICON_MAP_WAYPOINT, ACT_LOCATOR },