App structure: a swipe-in menu shell; pages/, link/, actions/; Settings

The shell (shell.dart): a drawer from the left edge or each page's menu button.
Dash, Signals, Captures; Tools (Camera, Link test, Orin power options), the
rarely used ones, after pirate-station-aide; Settings (gateway address, dark/bright,
build-time theme and landing). Landing view at build time: YUKART_HOME=dash|signals,
signals for now. Dash, Signals and Captures stay alive while hidden; Captures has its
own navigator, so a run survives switching views. Back goes inside Captures, then to
the landing view, then out. The mock banner sits over every page.

main.dart is startup only; the old home screen is pages/signals.dart; dialogs and
sheets moved to actions/; the protocol client, USB binding and Reading to link/.
lib/README.md catalogues it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

docs/impl/reports/LINK-TEST-2026-10-11.md

@@ -6,7 +6,7 @@ date: 2026-10-11
 
 Does the PD hub degrade the tablet ⇄ Orin USB (NCM) link? Measured from the app
 (the only place on the tablet whose sockets use the link) with the link test,
-`lib/linktest.dart` + `tool/linktest_server.py`.
+`lib/linktest.dart` (now `lib/pages/link_test.dart`) + `tool/linktest_server.py`.
 
 ## Short version