Show who is at the door: camera images on the Guition (0.2.66)

An alert from esp_screens_show_alert takes a `camera` (a camera.* or image.* entity): a Guition with firmware
0.2.57 shows that moment's picture across the top of the card, and a tap opens the camera full screen. A camera
or image tile opens the same full-screen view, refreshed every four seconds at a steady pace.

ESP Screen Manager fetches the snapshot with its own access, sizes it for the screen and serves a 24-bit BMP
under a random, short-lived link on port 8098; the screen loads it with ESPHome's online_image and holds no
Home Assistant token. BMP because ESPHome decodes it per chunk, where a full-screen JPEG held the loop 0.6 s.
The CYD keeps its alerts without the picture and gets no camera tiles.

The Guition also builds with ESPHome 2026.8+ again: backlight_fade.h derived from ESPHome's LEDC output, which
2026.8 made final, so the backlight now dims through ESPHome's own light transition.

Tested on the bench boards and a local add-on on the Home Assistant Yellow; docs/TEST_RESULTS_0266.md.

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

screen_manager/app/tile_icons.py

@@ -235,7 +235,7 @@ GLYPHS = {**{name: codepoint for name, (codepoint, _) in ICONS.items()}, **dict(
 # Mirrors runtime_tiles::icon_for() so the editor mockup shows what the screen draws.
 DEFAULTS = {'light': 'lightbulb', 'climate': 'air-conditioner', 'vacuum': 'robot-vacuum', 'fan': 'fan',
             'cover': 'window-shutter', 'scene': 'sofa', 'script': 'sofa', 'sensor': 'gauge', 'binary_sensor': 'gauge',
-            'timer': 'timer-outline', 'person': 'account', 'screen': 'clock-outline'}
+            'timer': 'timer-outline', 'person': 'account', 'camera': 'cctv', 'image': 'cctv', 'screen': 'clock-outline'}
 # The cards the screen brings itself: one icon per entity, not per domain.
 BUILTIN_TILES = {'screen.clock': 'clock-outline', 'screen.settings': 'cog'}
 FALLBACK = 'power'