v0.2.0: browser control (not tested on hardware yet)

ESP-Drone with browser control, v0.2.0. Not tested on real hardware yet:
remove the propellers and work through the bench checklist in
docs/e1-mini.md before the first flight.

Install

In the browser: https://technikweber.github.io/esp-drone/ (Chrome or Edge on a computer,
one click). Other ways, including Espressif's own tools:
docs/flashing.md.

Each file is a complete image for address 0x0:

File	Board	Chip
espdrone-e1-mini-esp32.bin	E1 Mini ("ESP32 Drone" kit)	ESP32
espdrone-s2-drone-esp32s2.bin	Espressif ESP32-S2-Drone	ESP32-S2
espdrone-s2-drone-esp32s3.bin	Espressif ESP32-S2-Drone with ESP32-S3	ESP32-S3

esptool.py --chip esp32 --port /dev/ttyUSB0 --baud 921600 write_flash 0x0 espdrone-e1-mini-esp32.bin

Back up the factory firmware first if you want to go back (read_flash 0 ALL, see the guide).
From the box to the first hover:
docs/getting-started.md.

What's in it

• Browser control over the drone's Wi-Fi with a captive portal: WebSocket, only the newest
  command counts, late commands are dropped, staged failsafe (hold, level out, descend, off).
• Battery protection: forced landing below 3.0 V, no arming below 3.4 V.
• Roll and pitch trim, stored on the drone, and one-tap levelling on the ground.
  Control page in English and German.
• Board support for the E1 Mini (ESP32 DevKit, MPU6500 on SPI, 8520 motors) with controller
  gains from the vendor firmware.
• Based on espressif/esp-drone master@9d5a4f8, built with ESP-IDF 5.5.

SHA-256

be623db1e58be5f8225cc36f675b8ee196c7d1871bfa1965e17c2eb34bdcea82  espdrone-e1-mini-esp32.bin
6f6488fa85f2d4fd729668781b5abdbb29a8f614cc06a7278fbbe2ddf1633be3  espdrone-s2-drone-esp32s2.bin
60d99f157828129d6945b1abcc6170790fcb87b54bbd95d6af03bfe3cf7bf854  espdrone-s2-drone-esp32s3.bin