feat: add scoreboard with player names, per-category leaderboards, and themed tables

Add player_name column to games (migration included), with regex-based
validation and anti-abuse sanitization. New /scoreboard page shows recent
games from localStorage, popular categories with play counts, and top-10
per-category leaderboards sorted by completion time. Also includes
two-click reverse word matching, base URL prefix support for reverse-proxy
hosting, BasePageHandler refactoring, themed table CSS for all 5 themes,
and comprehensive test coverage for player names and scoreboard API.

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

static/css/theme.css

@@ -269,6 +269,28 @@ body {
     font-weight: 600;
 }
 
+/* Tables (scoreboard) */
+.table {
+    color: var(--text-primary);
+    border-color: var(--indigo-mid);
+}
+
+.table > :not(caption) > * > * {
+    background-color: var(--indigo-dark);
+    border-bottom-color: var(--indigo-mid);
+    color: var(--text-primary);
+}
+
+.table-hover > tbody > tr:hover > * {
+    background-color: var(--indigo-mid);
+    color: var(--heading-color);
+}
+
+.table thead th {
+    color: var(--heading-color);
+    border-bottom-color: var(--indigo-mid);
+}
+
 /* Form controls */
 .form-select,
 .form-control {

static/js/game.js

@@ -1,6 +1,8 @@
 (function () {
     "use strict";
 
+    var BASE = document.body.dataset.baseUrl || "/";
+
     let gameState = null;
     let timerInterval = null;
     let selectedCells = [];
@@ -35,7 +37,7 @@
     // Load categories
     async function loadCategories() {
         try {
-            const resp = await fetch("/api/categories");
+            const resp = await fetch(BASE + "api/categories");
             if (!resp.ok) throw new Error("Server error");
             const categories = await resp.json();
             categorySelect.innerHTML = "";
@@ -65,7 +67,7 @@
             const boardSize = parseInt(boardSizeInput.value);
             const wordCount = parseInt(wordCountInput.value);
             const playerName = playerNameInput.value.trim();
-            const resp = await fetch("/api/game/new", {
+            const resp = await fetch(BASE + "api/game/new", {
                 method: "POST",
                 headers: { "Content-Type": "application/json" },
                 body: JSON.stringify({
@@ -253,7 +255,7 @@
     // Send guess to server
     async function sendGuess(payload) {
         try {
-            const resp = await fetch("/api/game/" + gameState.id + "/guess", {
+            const resp = await fetch(BASE + "api/game/" + gameState.id + "/guess", {
                 method: "POST",
                 headers: { "Content-Type": "application/json" },
                 body: JSON.stringify(payload),

static/js/scoreboard.js

@@ -1,6 +1,8 @@
 (function () {
     "use strict";
 
+    var BASE = document.body.dataset.baseUrl || "/";
+
     var loadingDiv = document.getElementById("scoreboard-loading");
     var recentSection = document.getElementById("recent-games-section");
     var recentTbody = document.querySelector("#recent-games-table tbody");
@@ -65,7 +67,7 @@
                 '  <div class="card-body">' +
                 '    <h5 class="card-title">' + escapeHtml(titleCase(c.name)) + '</h5>' +
                 '    <p class="card-text text-muted">' + c.completed_games + ' games completed</p>' +
-                '    <a href="/game" class="btn btn-accent btn-sm">Play</a>' +
+                '    <a href="' + BASE + 'game" class="btn btn-accent btn-sm">Play</a>' +
                 '  </div>' +
                 '</div>';
             popularRow.appendChild(col);
@@ -115,7 +117,7 @@
 
     async function loadScoreboard() {
         try {
-            var resp = await fetch("/api/scoreboard");
+            var resp = await fetch(BASE + "api/scoreboard");
             if (!resp.ok) throw new Error("Failed to load");
             var data = await resp.json();