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>

docs/developing.md

@@ -89,6 +89,14 @@ These addresses have no authentication. Any device on the network can use them.
 - The LD2450 reports target x mirrored. The stored setup keeps the radar's own frame. Code that draws radar readings or decides left and right must negate x.
 - The LD2450 sees about 60° to each side and about 6 m out. The wizard warns when part of the stairs is outside that area.
 
-## Not built
+## Browser installer
 
-- Installing a prebuilt firmware from a web browser.
+| Path | Contents |
+|---|---|
+| `installer/apollo-mtr-1.factory.yaml` | The installer firmware: `example/apollo-mtr-1.yaml` without Wi-Fi credentials, with Improv over USB serial and the access point |
+| `installer/index.html` | The installer page. `__VERSION__` is replaced with the release version. |
+| `.github/workflows/installer.yml` | Builds the firmware with ESPHome and publishes the page, the firmware and its manifest to GitHub Pages |
+
+The workflow runs on the GitHub mirror when a tag that starts with `v` arrives, for example `v2026.10.0`. The tag without the `v` becomes the firmware's project version. The site holds one firmware: the latest build.
+
+The installer firmware leaves out Improv over Bluetooth. With it, flash use goes from 69% to 91%.