touch: beta_68 — Lua SDK gains the map, lists, packet delivery and discovery

The four capabilities that kept third-party apps a sketch of a built-in one:

* wada.map      the firmware's own tiles, projection and cache inside an app
                page, with its own capped pool so it never evicts the Map tab's
* wada.ui.list  the missing "pick one of N" widget; rows are real buttons, so
                keyboard and trackball nav walk them for free
* on_packet     each frame delivered once instead of polling a 16-deep ring,
                which sampled rather than observed
* wada.mesh.discover  the active zero-hop probe, behind its own permission
                because it spends every neighbour's airtime, not just ours

Plus the surface those need to be useful: packet identity reported only where
the frame actually carries it, exact micro-degree coordinates (Lua is built
LUA_32BITS, so its floats were quietly costing a metre), altitude and satellite
time, wada.geo, wada.ui.input, named and one-shot timers, http_post, windowed
fs.read, and wada.sys.env on a hardware gate rather than the memory one.

Fixes:
* Both ESP32-P4 targets could not link. g_wifi_last_disc_reason was defined in
  src/main.cpp, which the IDF builds never compile, so all nine S3 envs stayed
  green while Tanmatsu and T-Display P4 were dead.
* Map zoom level was invisible in +/- buttons mode; the readout was hidden with
  the slider it was anchored to.
* Hungarian and Dutch held each other's "No SD card" translation.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/main.cpp

@@ -253,7 +253,12 @@ void halt() {
 // failure and AP-side rejection alike — the reason number tells them apart
 // (15 = 4-way handshake timeout ≈ wrong password; 2/202 = auth expired/failed
 // ≈ WPA3-only or auth mismatch; 201 = AP not found).
-volatile uint8_t g_wifi_last_disc_reason = 0;
+//
+// DEFINED in ui-touch/UITask.cpp, not here. The ESP32-P4 targets (Tanmatsu,
+// T-Display P4) are IDF builds with their own main.cpp and never compile this
+// file, so a definition here links on the S3 boards and leaves both P4 targets
+// with an undefined reference from the UI that reads it.
+extern volatile uint8_t g_wifi_last_disc_reason;
 #endif
 
 #include "esp_task_wdt.h"   // task-watchdog reconfigure — see setup() (GH #56)