build: add the ESP32-C5

The C5 builds like the C6: a debug build with one 3 MB app slot, so it
updates over USB. At CORE_DEBUG_LEVEL=2 its image left 3.4 KB of the
1.5 MB OTA slot, under CI's 8 KB.

- platformio.ini: env esp32c5 (esp32-c5-devkitc-1).
- Chip model "c5", so the updater and releases name its files
  SomfyController.*.esp32c5.bin.
- Radio defaults: the framework's SPI pins (CSN 6, MOSI 8, MISO 9,
  SCK 10), TX 4, RX 5.
- Web UI: GPIO 0-28, without 13-14 (USB) and 15-22 (flash, PSRAM).
- CI builds and releases it; its bootloader sits at 0x2000.
- ADR 0003: amended.

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

data-src/index.js

@@ -2719,6 +2719,7 @@ class Somfy {
         { name: 's2', maxPins: 46, inputs: [0, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 45], outputs: [0, 19, 20, 26, 27, 28, 29, 30, 31, 32, 45, 46]},
         { name: 's3', maxPins: 48, inputs: [19, 20, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32], outputs: [19, 20, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32] },
         { name: 'c3', maxPins: 21, inputs: [11, 12, 13, 14, 15, 16, 17, 18, 19, 20], outputs: [11, 12, 13, 14, 15, 16, 17, 21] },
+        { name: 'c5', maxPins: 28, inputs: [13, 14, 15, 16, 17, 18, 19, 20, 21, 22], outputs: [13, 14, 15, 16, 17, 18, 19, 20, 21, 22] },
         { name: 'c6', maxPins: 23, inputs: [], outputs: [] }
     ];