🔵 Add missing documentation: web UI guide, troubleshooting, changelog, 404, SEO descriptions

[drewferg11-hermes-bot]

Goal

Add missing documentation pages identified in the site review — the docs site currently lacks several pages that would significantly improve the user experience.

Missing pages

1. Web UI / settings page documentation

The FAQ mentions MQTT support, display modes (custom text, time, date, accuracy test), per-row control, and OTA configuration — but there's no dedicated page documenting the web interface itself. A new user who flashes the firmware has to discover the settings page by clicking around.

Add: firmware/web-interface.md covering:

• Settings page layout
• Wi-Fi configuration
• MQTT / Home Assistant setup
• Display modes and their options
• Module count configuration
• OTA password setup
• Serial console
• Screenshots

2. Mechanical/assembly troubleshooting guide

The FAQ has accuracy issue guidance (buried in a collapsible) and the firmware page has flasher troubleshooting — but there's no dedicated troubleshooting page for mechanical problems: flaps catching, modules not homing, motors stalling, DIP switch misconfiguration, etc.

Add: build/troubleshooting.md or firmware/troubleshooting.md

3. Changelog / release notes in docs

The repo has a GitHub Releases page but the docs site has no changelog. Users have to leave the site to see what changed between versions.

Add: changelog.md page under the Firmware section (or auto-generate from GitHub releases).

4. Custom 404 page

GitHub Pages serves a default 404. MkDocs Material supports a custom docs/404.md.

Add: docs/404.md with a friendly message and links to key pages.

5. Page descriptions for SEO

Only install-troubleshooting.md and install-web-flasher.md have description: frontmatter. Add description: to each page for better SEO and search snippets.

Acceptance criteria

• Web UI page exists with screenshots of the settings page, MQTT config, and display modes
• Troubleshooting page exists covering at least: flaps catching, modules not homing, motors stalling, DIP switch misconfiguration
• Changelog page exists and lists at least the last 3 releases
• Custom 404 page exists and renders in the Material theme
• All doc pages have description: frontmatter
• mkdocs build --strict passes
• New pages added to mkdocs.yml nav

Files / areas involved

• docs/firmware/web-interface.md (new)
• docs/firmware/troubleshooting.md or docs/build/troubleshooting.md (new)
• docs/firmware/changelog.md (new)
• docs/404.md (new)
• All existing docs/**/*.md files (add description frontmatter)
• mkdocs.yml (nav updates)

Constraints

• Screenshots should be hosted in docs/assets/web-ui/
• Don't duplicate FAQ content — link to the FAQ where it already covers a topic well
• Changelog can be auto-generated from GitHub releases or manually maintained