Add dirty check to all remaining editor modals

Subclass Modal with snapshotValues() for: value source editor, audio
source editor, add device, profile editor, capture template, stream
editor, and PP template modals. Close/cancel now triggers discard
confirmation when form has unsaved changes. Document the convention
in CLAUDE.md.

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

server/src/wled_controller/static/js/features/profiles.js

@@ -9,7 +9,21 @@ import { showToast, showConfirm } from '../core/ui.js';
 import { Modal } from '../core/modal.js';
 import { CardSection } from '../core/card-sections.js';
 
-const profileModal = new Modal('profile-editor-modal');
+class ProfileEditorModal extends Modal {
+    constructor() { super('profile-editor-modal'); }
+
+    snapshotValues() {
+        return {
+            name: document.getElementById('profile-editor-name').value,
+            enabled: document.getElementById('profile-editor-enabled').checked.toString(),
+            logic: document.getElementById('profile-editor-logic').value,
+            conditions: JSON.stringify(getProfileEditorConditions()),
+            targets: JSON.stringify(getProfileEditorTargetIds()),
+        };
+    }
+}
+
+const profileModal = new ProfileEditorModal();
 const csProfiles = new CardSection('profiles', { titleKey: 'profiles.title', gridClass: 'devices-grid', addCardOnclick: "openProfileEditor()" });
 
 // Re-render profiles when language changes (only if tab is active)
@@ -176,10 +190,11 @@ export async function openProfileEditor(profileId) {
     modal.querySelectorAll('[data-i18n]').forEach(el => {
         el.textContent = t(el.getAttribute('data-i18n'));
     });
+    profileModal.snapshot();
 }
 
-export function closeProfileEditorModal() {
-    profileModal.forceClose();
+export async function closeProfileEditorModal() {
+    await profileModal.close();
 }
 
 async function loadProfileTargetChecklist(selectedIds) {