docs: restructure docs for MkDocs site, add GitHub Pages workflow

- Reorganize 14 source docs into architecture/, deployment/, labs/, project/, contributing/ subdirs
- Add docs/index.md home page with full module table, architecture overview, phase tabs
- Add mkdocs.yml with Material theme — tabs, dark mode, search, code copy
- Add .github/workflows/docs.yml for auto-deploy to GitHub Pages
- Add requirements-docs.txt (mkdocs-material, minify)
- Remove 3 duplicate/timestamped doc files

Author: RedjiJB

.github/workflows/docs.yml

@@ -0,0 +1,56 @@
+name: Deploy Documentation to GitHub Pages
+
+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: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+          cache: pip
+
+      - name: Install MkDocs and plugins
+        run: pip install -r requirements-docs.txt
+
+      - name: Build documentation
+        run: mkdocs build --strict
+
+      - name: Upload Pages artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: site/
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deploy.outputs.page_url }}
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deploy
+        uses: actions/deploy-pages@v4