feat: orientation model, password confirm, frontend build

- Collapse orientation to landscape/portrait (ribbon left = portrait standard)
- Add OrientationPicker component and wire settings sheet in HomeView
- Add password confirmation field to registration form (RepeatedType)
- Build frontend SPA to public/build/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

firmware/platformio.ini

@@ -8,3 +8,19 @@ monitor_port = /dev/ttyUSB0
 board_build.filesystem = littlefs
 lib_deps =
     ricmoo/QRCode@^0.0.1
+
+; Flash a single image from firmware/data/img.bin — no WiFi, no server needed.
+; 1. pio run -e test-display --target uploadfs   (upload the image)
+; 2. pio run -e test-display --target upload      (upload the sketch)
+[env:test-display]
+platform = espressif32
+board = esp32dev
+framework = arduino
+monitor_speed = 115200
+upload_port = /dev/ttyUSB0
+monitor_port = /dev/ttyUSB0
+board_build.filesystem = littlefs
+build_flags = -DENV_TEST_DISPLAY
+build_src_filter = +<epd.cpp> +<test_display.cpp>
+lib_deps =
+    ricmoo/QRCode@^0.0.1