[docs] gh-pages deploy workflow + custom domain

- GitHub Actions workflow builds MkDocs and runs gh-deploy on push to the
  docs branch (full history checkout for git-revision-date; pip-cached)
- requirements.txt pins mkdocs/material/plugins to the local venv versions
- docs/CNAME carries docs.theprototype.app so the custom domain survives
  every gh-pages redeploy
- add site_url for canonical links + sitemap
- fix repo_url to the real remote (theprototype-app/docs) and edit_uri to
  the docs branch so the edit-pencil links resolve

Author: AlexZ005

.github/workflows/deploy.yml

@@ -0,0 +1,43 @@
+name: Deploy docs
+
+# Builds the MkDocs site and publishes it to the gh-pages branch.
+# GitHub Pages must be set (repo Settings > Pages) to "Deploy from a branch"
+# -> gh-pages / (root). The custom domain is carried by docs/CNAME.
+
+on:
+  push:
+    branches:
+      - docs
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+concurrency:
+  group: deploy-docs
+  cancel-in-progress: false
+
+jobs:
+  build-deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          # git-revision-date reads the full history for per-page dates.
+          fetch-depth: 0
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+          cache: pip
+
+      - name: Install dependencies
+        run: pip install -r requirements.txt
+
+      - name: Configure git identity
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+
+      - name: Build and deploy to gh-pages
+        run: mkdocs gh-deploy --force --clean

docs/CNAME

@@ -0,0 +1 @@
+docs.theprototype.app

mkdocs.yml

@@ -1,4 +1,5 @@
 site_name: ThePrototype Docs
+site_url: https://docs.theprototype.app/
 nav:
   - Getting Started:
     - Welcome: index.md
@@ -113,8 +114,8 @@ theme:
     edit: material/pencil
     view: material/eye
 
-repo_url: https://github.com/theprototype-docs/docs
-edit_uri: edit/main/
+repo_url: https://github.com/theprototype-app/docs
+edit_uri: edit/docs/
 
 markdown_extensions:
   - attr_list

requirements.txt

@@ -0,0 +1,7 @@
+# Pinned to match the local venv so CI builds reproduce local output.
+mkdocs==1.6.1
+mkdocs-material==9.5.49
+mkdocs-material-extensions==1.3.1
+mkdocs-git-revision-date-plugin==0.3.2
+pymdown-extensions==10.14
+Pygments==2.19.1