docs: add MkDocs Material documentation website

Renders the root markdown (manual, tools, changelog) into a static, searchable
HTML site with client-side (lunr.js) search and a dark/light theme. Built in
Docker via website/build-docs.sh (no host installs). Public URL is set at build
time with SITE_URL=... (default is a neutral placeholder; the site works at any
URL since site_url only affects the sitemap/canonical links). Generated output
(website/_build/) is gitignored.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -5,3 +5,6 @@ codec_bin_section_1.bin
 # Generated language plugin files + host-side builder binary
 *.gla
 languages_builder
+
+# Generated docs site
+website/_build/

CHANGELOG.md

@@ -11,6 +11,10 @@ single running list until the first versioned release.
   OpenGD77 features and FreeTRX additions, each tagged 🟢 [FreeTRX] or ⚪
   [OpenGD77]. Includes the spectrum scope (VFO sweep, hold `#`), channel add/delete,
   mute, dimming, and a button reference.
+- **Documentation website** (`website/`) — MkDocs Material config that renders the
+  markdown into a static, searchable HTML site (client-side search, dark/light
+  theme). Built in Docker via `./website/build-docs.sh`; the public URL is set with
+  `SITE_URL=…`. For self-hosting on Forgejo.
 
 ## 0.4.0
 

website/build-docs.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+#
+# Build the FreeTRX documentation website (MkDocs Material) entirely in Docker.
+# Source markdown lives in the repo root; this assembles it into _build/docs and
+# renders a static, self-contained HTML site with client-side search into
+# website/_build/site.
+#
+# Usage:  ./website/build-docs.sh          # build
+#         ./website/build-docs.sh serve    # live-reload preview on http://localhost:8000
+set -euo pipefail
+
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ROOT="$(cd "$HERE/.." && pwd)"
+SRC="$HERE/_build/docs"
+IMAGE="squidfunk/mkdocs-material:9"
+
+# ---- assemble the docs source tree from the root markdown -----------------
+rm -rf "$HERE/_build"
+mkdir -p "$SRC/images"
+
+cp "$HERE/home.md"      "$SRC/index.md"
+cp "$ROOT/MANUAL.md"    "$SRC/MANUAL.md"
+cp "$ROOT/TOOLS.md"     "$SRC/TOOLS.md"
+cp "$ROOT/CHANGELOG.md" "$SRC/CHANGELOG.md"
+cp "$ROOT"/docs/images/*.png "$SRC/images/" 2>/dev/null || true
+
+# MANUAL.md links back to README.md (a repo file, not a site page) -> point it at
+# the site home instead.
+sed -i.bak 's#(README.md)#(index.md)#g' "$SRC/MANUAL.md" && rm -f "$SRC/MANUAL.md.bak"
+
+# Optional public URL (sitemap / canonical only). Set SITE_URL to override the
+# placeholder in mkdocs.yml — the site works at any URL regardless.
+ENVARGS=()
+if [[ -n "${SITE_URL:-}" ]]; then
+	echo "==> Site URL: $SITE_URL"
+	ENVARGS=(-e "SITE_URL=$SITE_URL")
+fi
+
+# ---- build (or serve) -----------------------------------------------------
+if [[ "${1:-}" == "serve" ]]; then
+	echo "==> Serving docs on http://localhost:8000 (Ctrl-C to stop)"
+	docker run --rm -it -p 8000:8000 "${ENVARGS[@]+"${ENVARGS[@]}"}" -v "$HERE":/docs "$IMAGE" serve -a 0.0.0.0:8000
+else
+	echo "==> Building docs site"
+	docker run --rm "${ENVARGS[@]+"${ENVARGS[@]}"}" -v "$HERE":/docs "$IMAGE" build
+	echo
+	echo "==> Done. Static site (upload the *contents* of this folder):"
+	echo "    $HERE/_build/site"
+fi

website/home.md

@@ -0,0 +1,35 @@
+# FreeTRX
+
+**FreeTRX** is a fork of the [OpenGD77](https://opengd77.org) firmware for the
+**TYT MD-UV380 / Retevis RT-3S** and **Baofeng DM-1701 / Retevis RT-84**.
+
+[Latest release :material-download:](https://git.dk1da.de/DK1DA/FreeTRX/releases){ .md-button .md-button--primary }
+[Source :material-git:](https://git.dk1da.de/DK1DA/FreeTRX){ .md-button }
+
+## Screenshots
+
+<div class="grid cards" markdown>
+
+![DMR call with the segmented S-meter](images/screenshot-dmr.png)
+
+![VFO with the 7-segment frequency font](images/screenshot-vfo.png)
+
+</div>
+
+## Documentation
+
+- **[User Manual](MANUAL.md)** — every feature, tagged 🟢 **FreeTRX** (new/changed)
+  or ⚪ **OpenGD77** (inherited), with a button reference.
+- **[Building & Flashing](TOOLS.md)** — Docker build, the flash helper, screenshots.
+- **[Changelog](CHANGELOG.md)** — version history.
+
+## Supported radios
+
+Developed and tested on the **TYT MD-UV380 / Retevis RT-3S**. A DM-1701 / RT-84
+build is also produced but not yet officially tested. Want to help test another
+OpenGD77-supported radio? Email **Marcus, DK1DA** at
+[qsl@dk1da.de](mailto:qsl@dk1da.de).
+
+!!! note "License"
+    FreeTRX inherits the OpenGD77 license (modified BSD 3-Clause with a
+    non-commercial clause). It is not GPL-compatible and cannot be relicensed.

website/mkdocs.yml

@@ -0,0 +1,63 @@
+site_name: FreeTRX Documentation
+site_description: User manual for the FreeTRX firmware (an OpenGD77 fork for MD-UV380 / DM-1701)
+site_author: Marcus, DK1DA
+# Public URL where the docs are hosted. Only affects the sitemap / canonical links /
+# search-share URLs — the site itself works at ANY domain or path (relative links).
+# Override at build time without editing this file:  SITE_URL=https://your.url/ ./build-docs.sh
+site_url: !ENV [SITE_URL, "https://docs.example.com/"]
+repo_name: DK1DA/FreeTRX
+repo_url: https://git.dk1da.de/DK1DA/FreeTRX
+
+# Source markdown is assembled into _build/docs by build-docs.sh; output goes to _build/site.
+docs_dir: _build/docs
+site_dir: _build/site
+use_directory_urls: true
+
+theme:
+  name: material
+  language: en
+  palette:
+    - media: "(prefers-color-scheme: light)"
+      scheme: default
+      primary: green
+      accent: green
+      toggle:
+        icon: material/weather-night
+        name: Switch to dark mode
+    - media: "(prefers-color-scheme: dark)"
+      scheme: slate
+      primary: green
+      accent: green
+      toggle:
+        icon: material/weather-sunny
+        name: Switch to light mode
+  features:
+    - navigation.top
+    - navigation.sections
+    - navigation.instant
+    - search.suggest
+    - search.highlight
+    - search.share
+    - content.code.copy
+    - toc.follow
+
+plugins:
+  - search   # built-in client-side (lunr.js) full-text search — no external service
+
+nav:
+  - Home: index.md
+  - User Manual: MANUAL.md
+  - Building & Flashing: TOOLS.md
+  - Changelog: CHANGELOG.md
+
+markdown_extensions:
+  - admonition
+  - attr_list
+  - tables
+  - toc:
+      permalink: true
+  - pymdownx.superfences
+  - pymdownx.highlight
+  - pymdownx.emoji:
+      emoji_index: !!python/name:material.extensions.emoji.twemoji
+      emoji_generator: !!python/name:material.extensions.emoji.to_svg