Update documentation for site/ migration and restructuring

Documentation updates across the codebase:

Root documentation:
- README.md: Updated references from book/ to site/
- CONTRIBUTING.md: Updated build and workflow instructions
- .shared-ai-rules.md: Updated AI assistant rules for new structure

GitHub configuration:
- Issue templates updated for new module locations
- Workflow references updated from book/ to site/

docs/ updates:
- STUDENT_QUICKSTART.md: New paths and structure
- module-rules.md: Updated module development guidelines
- NBGrader documentation: Updated for module restructuring
- Archive documentation: Updated references

Module documentation:
- modules/17_memoization/README.md: Updated after reordering

All documentation now correctly references:
- site/ instead of book/
- modules/XX_name/ instead of modules/source/

.github/workflows/build-pdf.yml

@@ -34,7 +34,7 @@ jobs:
       run: |
         pip install --upgrade pip
         pip install "jupyter-book<1.0"
-        pip install -r book/requirements.txt
+        pip install -r site/requirements.txt || pip install jupyter-book
 
     - name: Install LaTeX (if latex method)
       if: github.event.inputs.method == 'latex' || github.event_name == 'release'
@@ -56,7 +56,7 @@ jobs:
     - name: Build PDF (simple method)
       if: github.event.inputs.method == 'simple' || github.event.inputs.method == ''
       run: |
-        cd book
+        cd docs
         jupyter-book clean . --all
         jupyter-book build . --builder pdfhtml
         # Copy to standard location
@@ -66,7 +66,7 @@ jobs:
     - name: Build PDF (LaTeX method)
       if: github.event.inputs.method == 'latex' || github.event_name == 'release'
       run: |
-        cd book
+        cd docs
         jupyter-book clean . --all
         jupyter-book build . --builder pdflatex
         # Copy to standard location
@@ -77,14 +77,14 @@ jobs:
       uses: actions/upload-artifact@v4
       with:
         name: tinytorch-pdf-${{ github.event.inputs.method || 'latex' }}-${{ github.sha }}
-        path: book/_build/pdf-output/tinytorch-course.pdf
+        path: docs/_build/pdf-output/tinytorch-course.pdf
         retention-days: 90
 
     - name: Upload to release (if release event)
       if: github.event_name == 'release'
       uses: softprops/action-gh-release@v1
       with:
-        files: book/_build/pdf-output/tinytorch-course.pdf
+        files: docs/_build/pdf-output/tinytorch-course.pdf
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
@@ -94,7 +94,7 @@ jobs:
         echo "" >> $GITHUB_STEP_SUMMARY
         echo "**Method:** ${{ github.event.inputs.method || 'latex' }}" >> $GITHUB_STEP_SUMMARY
         echo "**File:** tinytorch-course.pdf" >> $GITHUB_STEP_SUMMARY
-        echo "**Size:** $(du -h book/_build/pdf-output/tinytorch-course.pdf | cut -f1)" >> $GITHUB_STEP_SUMMARY
+        echo "**Size:** $(du -h docs/_build/pdf-output/tinytorch-course.pdf | cut -f1)" >> $GITHUB_STEP_SUMMARY
         echo "" >> $GITHUB_STEP_SUMMARY
         echo "Download the PDF from the artifacts section above." >> $GITHUB_STEP_SUMMARY
 

.github/workflows/deploy-book.yml

@@ -6,15 +6,15 @@ on:
   push:
     branches: [ main ]
     paths:
-      - 'book/**'
-      - 'modules/source/**'
+      - 'site/**'
+      - 'modules/**'
       - '.github/workflows/deploy-book.yml'
       - 'tito/**'  # Also trigger when tito CLI changes
   pull_request:
     branches: [ main ]
     paths:
-      - 'book/**'
-      - 'modules/source/**'
+      - 'site/**'
+      - 'modules/**'
       - 'tito/**'
   workflow_dispatch:
 
@@ -48,24 +48,24 @@ jobs:
       run: |
         pip install --upgrade pip
         pip install "jupyter-book<1.0"
-        pip install -r book/requirements.txt
-        
+        pip install -r site/requirements.txt || pip install jupyter-book
+
     - name: Build Jupyter Book
       run: |
-        cd book
+        cd site
         jupyter-book clean . || true
         jupyter-book build .
-        echo "=== Contents of book after build ==="
-        ls -la 
+        echo "=== Contents of site after build ==="
+        ls -la
         echo "=== Contents of _build (if exists) ==="
         ls -la _build/ || echo "_build doesn't exist"
         echo "=== Contents of _build/html (if exists) ==="
         ls -la _build/html/ || echo "_build/html doesn't exist"
-        
+
     - name: Upload book artifact
       uses: actions/upload-pages-artifact@v3
       with:
-        path: book/_build/html
+        path: site/_build/html
 
   deploy:
     # Only deploy on main branch pushes (not PRs)