feat: add MkDocs documentation and config module (#964)

- Set up MkDocs Material for docs.openadapt.ai
- Add unified config module with pydantic-settings
- Add example scripts for capture-train-eval and demo-retrieval workflows
- Add GitHub Actions workflow for automatic docs deployment

Author: abrichr

.github/workflows/docs.yml

@@ -0,0 +1,69 @@
+name: Deploy Documentation
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'docs/**'
+      - 'mkdocs.yml'
+      - '.github/workflows/docs.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - name: Cache pip
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/pip
+          key: ${{ runner.os }}-pip-mkdocs-${{ hashFiles('mkdocs.yml') }}
+          restore-keys: |
+            ${{ runner.os }}-pip-mkdocs-
+
+      - name: Install dependencies
+        run: |
+          pip install --upgrade pip
+          pip install mkdocs-material mkdocs-minify-plugin
+
+      - name: Build documentation
+        run: mkdocs build --strict
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v4
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: site
+
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

docs/CNAME

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+docs.openadapt.ai