feat: Add book viewer at /book with shared design system

- Add html/index.html: book viewer with auto-discovering sidebar,
  prev/next navigation, keyboard shortcuts, and URL hash persistence
- Add html/book-page.css: shared stylesheet for all book pages derived
  from fabula-ultima-sheet.css (dark theme, CSS variables, Cinzel/
  Crimson Text fonts, common class styles)
- Add book.js entry point so webpack injects the shared CSS into the
  book viewer; update webpack.config.js for two entry points, split
  CSS chunk, CopyWebpackPlugin for book pages, and /book dev server
  rewrite rule
- Add scripts/strip_watermark.py: removes "Guest Customer (Order
  #52072168)" watermark artifacts from all 210 book pages
- Add scripts/restyle_book.py: strips per-page <style> blocks and
  injects <link rel="stylesheet" href="book-page.css"> into all pages
- Update Justfile deploy to scp -r dist/* for the new /book subtree

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

webpack.config.js

@@ -2,14 +2,19 @@ const path = require('path');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
 const MiniCssExtractPlugin = require('mini-css-extract-plugin');
 const CssMinimizerPlugin = require('css-minimizer-webpack-plugin');
+const CopyWebpackPlugin = require('copy-webpack-plugin');
 
 module.exports = (env, argv) => {
   const isProd = argv.mode === 'production';
 
   return {
-    entry: './fabula-ultima-sheet.js',
+    entry: {
+      sheet: './fabula-ultima-sheet.js',
+      // Imports the shared CSS so HtmlWebpackPlugin can inject it into the book page
+      book: './book.js',
+    },
     output: {
-      filename: isProd ? 'bundle.[contenthash].js' : 'bundle.js',
+      filename: isProd ? '[name].[contenthash].js' : '[name].js',
       path: path.resolve(__dirname, 'dist'),
       clean: true,
       // Disable IIFE wrapping so onclick= handlers can reach global functions
@@ -28,21 +33,59 @@ module.exports = (env, argv) => {
     },
     plugins: [
       ...(isProd
-        ? [new MiniCssExtractPlugin({ filename: 'styles.[contenthash].css' })]
+        ? [new MiniCssExtractPlugin({ filename: '[name].[contenthash].css' })]
         : []),
       new HtmlWebpackPlugin({
         template: './fabula-ultima-sheet.html',
         filename: 'index.html',
+        chunks: ['sheet'],
         scriptLoading: 'blocking',
       }),
+      new HtmlWebpackPlugin({
+        template: './html/index.html',
+        filename: 'book/index.html',
+        chunks: ['book'],
+        scriptLoading: 'blocking',
+      }),
+      // Copy book pages to dist/book/ (excluding index.html, managed by HtmlWebpackPlugin)
+      new CopyWebpackPlugin({
+        patterns: [
+          {
+            from: 'html',
+            to: 'book',
+            globOptions: { ignore: ['**/index.html'] },
+          },
+        ],
+      }),
     ],
     optimization: {
       minimizer: ['...', new CssMinimizerPlugin()],
+      splitChunks: {
+        cacheGroups: {
+          // Merge CSS from all entries into a single shared file
+          styles: {
+            name: 'styles',
+            type: 'css/mini-extract',
+            chunks: 'all',
+            enforce: true,
+          },
+        },
+      },
     },
     devServer: {
-      static: { directory: path.resolve(__dirname, 'dist') },
+      static: [
+        { directory: path.resolve(__dirname, 'dist') },
+        // Serve raw html/ pages at /book in dev so they don't need to be copied
+        { directory: path.resolve(__dirname, 'html'), publicPath: '/book' },
+      ],
       port: 8080,
       open: true,
+      historyApiFallback: {
+        rewrites: [
+          // /book (no trailing slash) → /book/index.html
+          { from: /^\/book$/, to: '/book/index.html' },
+        ],
+      },
     },
   };
 };