feat(route): path editor with out-and-back trace and a kept route; map markers as one drawn layer

Core: PathEditor (UiCore::route) loads, edits, traces and saves the route to
a contact; MyMesh::sendTrace over an explicit route with per-hop SNRs,
setContactPath / setContactPinned. A route can be kept
(CONTACT_FLAG_ROUTE_PINNED, ContactInfo::flags bit 4): a path heard from the
node doesn't replace it and the last DM resend doesn't drop it.

ui-lvgl: Route screen (node detail), repeater picker by distance, picking
hops by tapping the nodes map (numbered badges, line, Undo / Done). The
map's markers are one drawn layer with hit-testing and name decluttering
instead of three objects per node.

ui-new: Path / trace view in the Nodes action menu; Add reuses the list
filtered to repeaters.

First cut: built for L2 LVGL, L1 OLED and L1 e-ink, tried on L2 only.

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

src/helpers/ContactInfo.h

@@ -5,6 +5,12 @@
 
 #define OUT_PATH_UNKNOWN   0xFF
 
+// ContactInfo::flags bit 4: the route in out_path was set by hand (the device's
+// Route editor) and is kept: a path heard from the contact, or a message that
+// goes unanswered, doesn't replace it. Bit 0 is the favourite star, bits 1-3 the
+// telemetry permissions. Reset path (or a new route saved) clears / sets it.
+#define CONTACT_FLAG_ROUTE_PINNED  0x10
+
 struct ContactInfo {
   mesh::Identity id;
   char name[32];