feat(route): Discover - path discovery from the device, 1/3/5 tries 20 s apart, the routes found to use in the route editor

MyMesh::sendPathDiscovery() shares the request with the app's
CMD_SEND_PATH_DISCOVERY_REQ and hands the reply (the way there and back)
to the UI; PathEditor keeps up to 4 distinct routes with how often each
came. L2: Find the route under Route; L1: Discover row in Path / trace.
Docs: Discover, message routes on the map, Ask status and discovery.

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

docs/solo/messages.md

@@ -30,10 +30,20 @@ older and newer one.
   contains a location (see [Navigation](./navigation.md)).
 - **Path** on a received message: the repeaters it came through.
   **Relayed by** on your own channel post: the repeaters heard repeating it.
+- **Show route**: when the message has a route written in it, such as a
+  bot's `!path` reply (`3f:a1:c8`, see [Remote bot](./tools.md#remote-bot)).
+  It draws the route on a small map: you, each repeater numbered in order,
+  and the sender, with how many of the hops could be placed (a repeater
+  needs a position). In a direct message the route starts from you, because
+  it's the way your message went; on a channel it's someone else's, so it
+  doesn't. **Back** closes it.
 
 > [!NOTE]
 > **Wio Tracker L2:** hold a bubble. The card shows when it was sent, the hop
-> count, the path as a diagram, and **Reply** / **Set target**.
+> count, the path as a diagram, and **Reply** / **Set target**, plus **Route**
+> when the message has a route in it: the nodes map opens with the route drawn
+> and its hops numbered, and the names along the bottom; **Done** goes back to
+> the conversation.
 
 ### How much is kept