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/

docs/_config_pdf.yml

@@ -0,0 +1,80 @@
+# TinyTorch: Build ML Systems from Scratch
+# PDF-Specific Configuration
+
+title: "TinyTorch: Build ML Systems from Scratch"
+author: "Prof. Vijay Janapa Reddi (Harvard University)"
+copyright: "2025"
+logo: ../site/_static/logos/logo-tinytorch-white.png
+
+# Book description
+description: >-
+  An interactive course for building machine learning systems from the ground up.
+  Learn by implementing your own PyTorch-style framework with hands-on coding,
+  real datasets, and production-ready practices.
+
+# Execution settings - disable for PDF
+execute:
+  execute_notebooks: "off"
+  allow_errors: false
+  timeout: 300
+
+# Exclude patterns
+exclude_patterns:
+  - _build
+  - .venv
+  - appendices
+  - "**/.venv/**"
+  - "**/__pycache__/**"
+  - "**/.DS_Store"
+
+# GitHub repository (for reference in PDF)
+repository:
+  url: https://github.com/mlsysbook/TinyTorch
+  path_to_book: docs
+  branch: main
+
+# LaTeX/PDF output configuration
+latex:
+  latex_engine: pdflatex
+  use_jupyterbook_latex: true
+  latex_documents:
+    targetname: tinytorch-course.tex
+
+# Bibliography support
+bibtex_bibfiles:
+  - ../site/references.bib
+
+# Sphinx extensions
+sphinx:
+  extra_extensions:
+    - sphinxcontrib.mermaid
+  config:
+    mermaid_version: "10.6.1"
+    # PDF-specific settings
+    latex_toplevel_sectioning: 'chapter'
+    latex_theme: 'manual'
+    latex_elements:
+      papersize: 'letterpaper'
+      pointsize: '10pt'
+      preamble: |
+        \usepackage{fancyhdr}
+        \pagestyle{fancy}
+        \fancyhead[LE,RO]{\thepage}
+        \fancyhead[LO]{\nouppercase{\rightmark}}
+        \fancyhead[RE]{\nouppercase{\leftmark}}
+
+# Parse configuration
+parse:
+  myst_enable_extensions:
+    - "colon_fence"
+    - "deflist"
+    - "html_admonition"
+    - "html_image"
+    - "linkify"
+    - "replacements"
+    - "smartquotes"
+    - "substitution"
+    - "tasklist"
+
+# Build only TOC files
+only_build_toc_files: true