fix(ui): confirm destructive actions, retire last Hold-Enter-cancel, de-dup labels

Continuing the consistency review: sweep for the same three defect shapes
elsewhere in ui-new/ (own read pass plus two parallel research agents),
verified against source before acting.

Three destructive actions fired on a single Enter with no way back, unlike
contact-delete's existing confirm-defaulted-to-Cancel popup: Trail's "Reset
trail" (wipes the whole recorded route, no undo short of a prior manual
Save -- reuses Trail's own multi-level menu machinery, alongside its
GPS-off confirm), Messages' channel Delete, and RadioPresetPicker's saved-
preset delete (shared by Settings > Radio and Tools > Repeater, so one fix
covers both). All three now confirm the same way, defaulting to Cancel.

KeyboardWidget was the one place Hold-Enter still doubled as Cancel: Shift,
Backspace and a Latin letter's accent popup already have real, kept
meanings under a hold, but every other special-row cell (Space, OK/Done,
the {} placeholder) fell through to a bare CANCELLED, closing the keyboard
exactly like the real Cancel key. Now a no-op there too, matching the "only
Back closes it" rule already applied to popups and screens.

MessagesScreen defined the same two label arrays (Notif states, melody
slots) four times over, once per context-menu handler. Hoisted to one
pair of static class members -- constexpr wasn't enough to get the linker
to emit them on this toolchain, so they follow the same declare-in-class/
define-out-of-class shape NearbyScreen::FILTER_LABELS already uses.

Alert text: "Advert sent!"/"Advert failed.." and "Sent!" were the only
toasts anywhere with trailing punctuation; normalized to the plain style
every other confirmation uses. Unpinning from the Favourites Dial reported
the freed slot number from the Messages screens but not from Nodes or the
dial's own tile menu; now consistent everywhere pinning already was.

DiagnosticsScreen's Live/System/Font tab renderers hand-rolled the same
scroll-clamp/loop/indicator skeleton drawList() already bundles; switched
both to drawList (passing the screen's own _scroll as its `sel` too, since
neither tab has a row cursor -- makes drawList's internal clamp a no-op and
leaves clampScroll() as the only thing bounding it, unchanged). Pure
internal tidy, no behavior change.

release-notes.md

@@ -20,7 +20,9 @@
 - **A location shared in a message could be navigated to and saved as a waypoint, but not set as the Locator target** — the one row that Nodes and Waypoints both offer for a coordinate. **Set as target** now joins Navigate and Save waypoint in the message Options menu.
 - **Tools › Nodes refused to make a Locator target out of a node whose full public key it didn't have**, even with a perfectly good position on screen — the row you get when someone shares their location on a channel and isn't in your contacts, which is exactly the group-outing case the feature is for. One flag was standing in for two different things: "can be pinged" (needs the whole 32-byte key) and "can be identified" (needs only a 6-byte prefix, which is all a person target ever uses). Those are separate now, so **Set as target** is offered whenever the node has a position: with an identity it follows them as they move, and without one — a channel share, matched by name — it pins the place they were last seen, the same way a waypoint or a location out of a message does. **Navigate** was never restricted and is unchanged.
 - **Tools › Locator's target picker listed the people pinned to the Favourites Dial as its top tier**, which stopped making sense once pinning and favouriting became separate things — pinning puts something on a home page, and has nothing to say about who you'd geofence. The picker now leads with your **favourites** instead (still offered before they have a known position, so you can arm ahead of time); everyone else with a resolvable position follows, as before.
-- **Hold Enter no longer doubles as a second Back key.** On Tools, Locator, Live Share, Repeater, Remote Bot, Auto-Advert, GPIO, Compass, the Dashboard config and the Messages navigate view it quietly meant "go back", while on other screens the same gesture opens a context menu — so the same long press did two unrelated things depending on where you were. It now only ever opens a menu (or does nothing where there is none), and Back is the single way back. This also applies inside an open popup, which Hold Enter used to dismiss.
+- **Hold Enter no longer doubles as a second Back key.** On Tools, Locator, Live Share, Repeater, Remote Bot, Auto-Advert, GPIO, Compass, the Dashboard config and the Messages navigate view it quietly meant "go back", while on other screens the same gesture opens a context menu — so the same long press did two unrelated things depending on where you were. It now only ever opens a menu (or does nothing where there is none), and Back is the single way back. This also applies inside an open popup, which Hold Enter used to dismiss — and, last of all, inside the on-screen keyboard: Hold Enter on Space, OK/Done or the `{}` placeholder cell used to close the keyboard exactly like Cancel; it's now a no-op there too, alongside its real jobs on Shift (caps-lock) and Backspace (clear field) and its accent popup on a Latin letter.
+- **Deleting a channel, deleting a saved radio preset, and Trail's "Reset trail" all fired immediately on a single Enter, with no way back.** Deleting a contact already asks first and defaults to Cancel; these three didn't, and Reset trail was the worst of them — it wipes the entire recorded GPS trail with no undo short of a prior manual Save, more destructive than the GPS-off prompt already sitting one menu over in the same screen. All three now confirm the same way contact-delete does.
+- **The one alert after a successful advert or message send didn't match the rest of the app's toasts.** `"Advert sent!"` / `"Advert failed.."` and `"Sent!"` were the only alerts anywhere with trailing punctuation; every other confirmation (`"Preset saved"`, `"Contact added"`, `"Target set"`, …) is bare. Also, unpinning something from the Favourites Dial reported which slot it came out of on some screens but not others — pinning always said so, unpinning only did from the Messages screens. Both now match the rest.
 
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