fix(web): address code review findings from Razor Pages migration

- Remove legacy wwwroot files (old index.html, app.css, api.js, page scripts)
- Add Index page that redirects / to /board
- Fix mapping delete button missing handler=Delete in URL
- Add [IgnoreAntiforgeryToken] to AnalyticsModel for consistency
- Remove duplicate JS from _TaskDetail.cshtml (already in app.js)

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

TaskTracker.Api/Pages/Partials/_MappingRow.cshtml

@@ -28,7 +28,7 @@
                 <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M17 3a2.85 2.85 0 1 1 4 4L7.5 20.5 2 22l1.5-5.5Z"/><path d="m15 5 4 4"/></svg>
             </button>
             <button class="btn btn--ghost btn--sm"
-                    hx-delete="/mappings?id=@Model.Id"
+                    hx-delete="/mappings?handler=Delete&id=@Model.Id"
                     hx-target="#mapping-row-@Model.Id"
                     hx-swap="outerHTML"
                     hx-confirm="Delete this mapping rule?"

TaskTracker.Api/Pages/Partials/_TaskDetail.cshtml

@@ -259,65 +259,4 @@
     }
 </div>
 
-<script>
-    // Open the detail panel when this partial is loaded
-    (function() {
-        var overlay = document.querySelector('.detail-overlay');
-        var panel = document.querySelector('.detail-panel');
-        // Use requestAnimationFrame to ensure the DOM is painted before adding classes
-        requestAnimationFrame(function() {
-            if (overlay) overlay.classList.add('detail-overlay--open');
-            if (panel) panel.classList.add('detail-panel--open');
-        });
-    })();
-
-    function closeDetailPanel() {
-        var overlay = document.querySelector('.detail-overlay');
-        var panel = document.querySelector('.detail-panel');
-        if (overlay) overlay.classList.remove('detail-overlay--open');
-        if (panel) panel.classList.remove('detail-panel--open');
-        // Clear the panel content after the transition
-        setTimeout(function() {
-            var container = document.getElementById('detail-panel');
-            if (container) container.innerHTML = '';
-        }, 300);
-    }
-
-    function startEdit(field) {
-        var wrapper = document.getElementById('edit-' + field);
-        if (!wrapper) return;
-        var display = wrapper.querySelector('.inline-edit-display');
-        var form = wrapper.querySelector('.inline-edit-form');
-        if (display) display.style.display = 'none';
-        if (form) {
-            form.style.display = '';
-            var input = form.querySelector('input, textarea');
-            if (input) {
-                input.focus();
-                if (input.type === 'text' || input.tagName === 'TEXTAREA') {
-                    input.setSelectionRange(input.value.length, input.value.length);
-                }
-            }
-        }
-    }
-
-    function cancelEdit(field) {
-        var wrapper = document.getElementById('edit-' + field);
-        if (!wrapper) return;
-        var display = wrapper.querySelector('.inline-edit-display');
-        var form = wrapper.querySelector('.inline-edit-form');
-        if (display) display.style.display = '';
-        if (form) form.style.display = 'none';
-    }
-
-    // Close panel on Escape key
-    document.addEventListener('keydown', function(e) {
-        if (e.key === 'Escape') {
-            var panel = document.querySelector('.detail-panel--open');
-            if (panel) {
-                closeDetailPanel();
-                e.stopPropagation();
-            }
-        }
-    });
-</script>
+<!-- Panel open/close, inline editing, and keyboard handling are in app.js -->