feat: add anime metadata editing and NFO diagnostics

- Add PUT /anime/{key} endpoint for updating anime key, tmdb_id, tvdb_id
- Add NFO diagnostics and repair endpoints (GET/POST /nfo/diagnostics)
- Add edit modal UI with context menu integration
- Add frontend JS modules for context-menu and edit-modal
- Add comprehensive tests for edit, rename, and NFO repair flows

src/server/web/static/js/index/context-menu.js

@@ -0,0 +1,123 @@
+/**
+ * AniWorld - Context Menu Component
+ *
+ * Right-click context menu for anime series cards.
+ * Provides quick access to edit metadata.
+ *
+ * Dependencies: ui-utils.js, edit-modal.js
+ */
+
+var AniWorld = window.AniWorld || {};
+
+AniWorld.ContextMenu = (function() {
+    'use strict';
+
+    let menuElement = null;
+    let currentSeriesKey = null;
+
+    /**
+     * Initialize the context menu system.
+     * Attaches global dismissal listeners.
+     */
+    function init() {
+        // Dismiss on click outside
+        document.addEventListener('click', function(e) {
+            if (menuElement && !menuElement.contains(e.target)) {
+                hide();
+            }
+        });
+
+        // Dismiss on Escape
+        document.addEventListener('keydown', function(e) {
+            if (e.key === 'Escape') {
+                hide();
+            }
+        });
+
+        // Dismiss on scroll or resize
+        window.addEventListener('scroll', hide, true);
+        window.addEventListener('resize', hide);
+
+        // Attach context menu via event delegation on the series grid
+        const grid = document.getElementById('series-grid');
+        if (grid) {
+            grid.addEventListener('contextmenu', function(e) {
+                const card = e.target.closest('.series-card');
+                if (card) {
+                    e.preventDefault();
+                    const key = card.getAttribute('data-key');
+                    if (key) {
+                        show(e, key);
+                    }
+                }
+            });
+        }
+    }
+
+    /**
+     * Show context menu at cursor position.
+     * @param {MouseEvent} event - The contextmenu event
+     * @param {string} seriesKey - The series key to operate on
+     */
+    function show(event, seriesKey) {
+        hide(); // Remove any existing menu first
+
+        currentSeriesKey = seriesKey;
+
+        menuElement = document.createElement('div');
+        menuElement.className = 'context-menu';
+        menuElement.innerHTML = `
+            <div class="context-menu-item" data-action="edit">
+                <i class="fa-solid fa-pen-to-square"></i>
+                <span>Edit Metadata</span>
+            </div>
+        `;
+
+        document.body.appendChild(menuElement);
+
+        // Position within viewport bounds
+        const x = event.clientX;
+        const y = event.clientY;
+        const menuRect = menuElement.getBoundingClientRect();
+        const viewportWidth = window.innerWidth;
+        const viewportHeight = window.innerHeight;
+
+        let posX = x;
+        let posY = y;
+
+        if (x + menuRect.width > viewportWidth) {
+            posX = viewportWidth - menuRect.width - 8;
+        }
+        if (y + menuRect.height > viewportHeight) {
+            posY = viewportHeight - menuRect.height - 8;
+        }
+
+        menuElement.style.left = posX + 'px';
+        menuElement.style.top = posY + 'px';
+
+        // Attach action handlers
+        menuElement.querySelector('[data-action="edit"]').addEventListener('click', function() {
+            hide();
+            if (AniWorld.EditModal) {
+                AniWorld.EditModal.open(currentSeriesKey);
+            }
+        });
+    }
+
+    /**
+     * Hide and remove the context menu from DOM.
+     */
+    function hide() {
+        if (menuElement) {
+            menuElement.remove();
+            menuElement = null;
+            currentSeriesKey = null;
+        }
+    }
+
+    return {
+        init: init,
+        show: show,
+        hide: hide
+    };
+})();