Browser installer on GitHub Pages

installer/apollo-mtr-1.factory.yaml is the example config without Wi-Fi
credentials, with Improv serial and the access point. A version tag on the
GitHub mirror builds it with esphome/build-action and publishes the page,
firmware and manifest to GitHub Pages.

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

README.md

@@ -41,7 +41,15 @@ All values for your stairs come from the setup wizard: the shape, the number of
 - The sensor and the WLED controller on the same network.
 - Straight, L-shaped or U-shaped stairs, with at most one landing.
 
-## Installing on an Apollo MTR-1
+## Installing from the browser
+
+Open the [follow-me installer](https://randompedestrian07.github.io/follow-me-stairs/) in Chrome or Edge on a computer, and connect the MTR-1 with a USB-C data cable. The installer flashes the firmware and then asks for your Wi-Fi. Installing erases the sensor. A sensor that already has a follow-me setup must go through the setup wizard again.
+
+The installer firmware has no Wi-Fi credentials. If the Wi-Fi step does not appear, connect a phone to the `Apollo MTR1 Hotspot` network and enter your Wi-Fi there.
+
+To change the firmware yourself, install with ESPHome instead.
+
+## Installing on an Apollo MTR-1 with ESPHome
 
 1. Copy `example/apollo-mtr-1.yaml` into your ESPHome configuration folder.
 2. Put this repository in the same folder, as a folder named `follow-me-stairs`.