docs: add MkDocs documentation site (#7200)

Author: pfeerick

.github/workflows/docs.yml

@@ -0,0 +1,55 @@
+name: Deploy Documentation
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'docs/**'
+      - 'mkdocs.yml'
+      - 'docs-requirements.txt'
+      - '.github/workflows/docs.yml'
+    tags:
+      - 'v[0-9]+.[0-9]+.[0-9]+'   # release tags only, not -rc
+  pull_request:
+    paths:
+      - 'docs/**'
+      - 'mkdocs.yml'
+      - 'docs-requirements.txt'
+      - '.github/workflows/docs.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v7
+
+      - name: Configure git for mike
+        if: github.event_name != 'pull_request'
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+      - name: Build docs (PR check)
+        if: github.event_name == 'pull_request'
+        run: uv run --with-requirements docs-requirements.txt mkdocs build --strict
+
+      - name: Deploy as latest (main branch)
+        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        run: uv run --with-requirements docs-requirements.txt mike deploy --push --update-aliases latest
+
+      - name: Deploy release version
+        if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
+        run: |
+          # Extract minor version from tag, e.g. v2.11.2 -> v2.11
+          VERSION=$(echo "${GITHUB_REF_NAME}" | sed 's/\.[0-9]*$//')
+          uv run --with-requirements docs-requirements.txt mike deploy --push --update-aliases "${VERSION}" stable

.gitignore

@@ -4,8 +4,8 @@
 /*.user
 /*.user.*
 /doc/
-build*/
-cmake-build-*/
+/build*/
+/cmake-build-*/
 /debian/
 /*.vscode
 radio/src/tests/googletest*

docs-requirements.txt

@@ -0,0 +1,4 @@
+mkdocs>=1.6
+mkdocs-material>=9.5
+mkdocs-minify-plugin>=0.8
+mike>=2.0