BOOK NOW, OpenStreetMap, and one segmented control instead of two

── The circle says what pressing it does ──

"ONE TOUCH" named the *mechanism* — one gesture, no form — which is something
the product team knows and a customer has to be taught. Nobody arrives at that
screen wanting a touch; they want a parcel collected. The caption under the
sphere still carries what makes it different from the form below.

Renamed in the comments too. A codebase explaining "One Touch" against a button
that says BOOK NOW is a trap for whoever reads it next.

── OpenStreetMap everywhere ──

One line: the default provider was CARTO, it is `osm`. Nothing else moves —
`DmMapTiles` already reads the template, subdomains, retina flag and
attribution off the provider, so the credit line follows on its own.

One thing recorded on the provider itself rather than left to be discovered:
these are donated servers and the OSM Foundation's tile policy does not permit
a distributed app to lean on them. A block looks like every tile turning into
the ground colour at once, with no other symptom. Moving off it is one define —
`DM_MAP_PROVIDER=carto|maptiler|stadia`, all serving OpenStreetMap data — and
the map_config test now asserts the identifying User-Agent rather than only the
URL, because that is what attributable traffic depends on.

── Orders had a second copy of the segmented control ──

Its own `_Tab`, a pill radius, 3pt of padding and the count folded into the
label's text — beside the pickup window's day switcher, which is DmChoiceChip
in a rounded groove with 4pt of padding and the count in a bubble. Two controls
doing one job, drifting apart a padding value at a time.

It is the same control now, and `_Tab` is gone. DmChoiceChip's horizontal
padding drops 12 → 9: three of them split a 390pt phone and "Cancelled"
truncated to "Cancell…" at the old value. The day switcher has two chips and
acres of room, so it loses nothing.

lib/state/app_state.dart

@@ -463,7 +463,7 @@ class AppState extends ChangeNotifier {
   ///
   /// ── Two ways to book the same parcel ──
   ///
-  /// **One Touch** asks three things: the state, the district and a pickup
+  /// **BOOK NOW** asks three things: the state, the district and a pickup
   /// window. Nothing else — no door number, no recipient, no weight. Those are
   /// filled in by the Miler standing at the address with the parcel in their
   /// hand, which is the only moment anybody actually knows them.