fix: Restore all files lost during destructive rebase

A previous `git pull --rebase origin main` dropped 177 local commits,
losing 3400+ files across admin-v2, backend, studio-v2, website,
klausur-service, and many other services. The partial restore attempt
(660295e2) only recovered some files.

This commit restores all missing files from pre-rebase ref 98933f5e
while preserving post-rebase additions (night-scheduler, night-mode UI,
NightModeWidget dashboard integration).

Restored features include:
- AI Module Sidebar (FAB), OCR Labeling, OCR Compare
- GPU Dashboard, RAG Pipeline, Magic Help
- Klausur-Korrektur (8 files), Abitur-Archiv (5+ files)
- Companion, Zeugnisse-Crawler, Screen Flow
- Full backend, studio-v2, website, klausur-service
- All compliance SDKs, agent-core, voice-service
- CI/CD configs, documentation, scripts

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

backend/frontend/modules/widgets/matrix_widget.py

@@ -0,0 +1,289 @@
+"""
+Matrix Chat Widget fuer das Lehrer-Dashboard.
+
+Zeigt die letzten Chat-Nachrichten aus dem Matrix Messenger.
+"""
+
+
+class MatrixWidget:
+    widget_id = 'matrix'
+    widget_name = 'Matrix-Chat'
+    widget_icon = '💬'  # Speech bubble
+    widget_color = '#8b5cf6'  # Purple
+    default_width = 'half'
+    has_settings = True
+
+    @staticmethod
+    def get_css() -> str:
+        return """
+/* ===== Matrix Widget Styles ===== */
+.widget-matrix {
+    background: var(--bp-surface, #1e293b);
+    border: 1px solid var(--bp-border, #475569);
+    border-radius: 12px;
+    padding: 16px;
+    height: 100%;
+    display: flex;
+    flex-direction: column;
+}
+
+.widget-matrix .widget-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    margin-bottom: 12px;
+    padding-bottom: 12px;
+    border-bottom: 1px solid var(--bp-border-subtle, rgba(255,255,255,0.1));
+}
+
+.widget-matrix .widget-title {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    font-size: 14px;
+    font-weight: 600;
+    color: var(--bp-text, #e5e7eb);
+}
+
+.widget-matrix .widget-icon {
+    width: 28px;
+    height: 28px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background: rgba(139, 92, 246, 0.15);
+    color: #8b5cf6;
+    border-radius: 8px;
+    font-size: 14px;
+}
+
+.widget-matrix .matrix-list {
+    flex: 1;
+    overflow-y: auto;
+}
+
+.widget-matrix .chat-item {
+    display: flex;
+    gap: 10px;
+    padding: 10px 0;
+    border-bottom: 1px solid var(--bp-border-subtle, rgba(255,255,255,0.05));
+    cursor: pointer;
+    transition: background 0.2s;
+}
+
+.widget-matrix .chat-item:last-child {
+    border-bottom: none;
+}
+
+.widget-matrix .chat-item:hover {
+    background: var(--bp-surface-elevated, #334155);
+    margin: 0 -12px;
+    padding: 10px 12px;
+    border-radius: 8px;
+}
+
+.widget-matrix .chat-avatar {
+    width: 32px;
+    height: 32px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background: rgba(139, 92, 246, 0.15);
+    color: #8b5cf6;
+    border-radius: 50%;
+    font-size: 12px;
+    flex-shrink: 0;
+}
+
+.widget-matrix .chat-content {
+    flex: 1;
+    min-width: 0;
+}
+
+.widget-matrix .chat-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-bottom: 2px;
+}
+
+.widget-matrix .chat-room {
+    font-size: 12px;
+    font-weight: 600;
+    color: var(--bp-text, #e5e7eb);
+}
+
+.widget-matrix .chat-time {
+    font-size: 10px;
+    color: var(--bp-text-muted, #9ca3af);
+}
+
+.widget-matrix .chat-message {
+    font-size: 12px;
+    color: var(--bp-text-muted, #9ca3af);
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+
+.widget-matrix .chat-unread {
+    width: 8px;
+    height: 8px;
+    background: #8b5cf6;
+    border-radius: 50%;
+    margin-left: 8px;
+}
+
+.widget-matrix .matrix-empty {
+    text-align: center;
+    padding: 24px;
+    color: var(--bp-text-muted, #9ca3af);
+    font-size: 13px;
+}
+
+.widget-matrix .matrix-empty-icon {
+    font-size: 32px;
+    margin-bottom: 8px;
+    opacity: 0.5;
+}
+
+.widget-matrix .matrix-footer {
+    margin-top: 12px;
+    padding-top: 12px;
+    border-top: 1px solid var(--bp-border-subtle, rgba(255,255,255,0.1));
+}
+
+.widget-matrix .matrix-all-btn {
+    width: 100%;
+    padding: 10px;
+    background: transparent;
+    border: 1px dashed var(--bp-border, #475569);
+    border-radius: 8px;
+    color: var(--bp-text-muted, #9ca3af);
+    font-size: 12px;
+    cursor: pointer;
+    transition: all 0.2s;
+}
+
+.widget-matrix .matrix-all-btn:hover {
+    border-color: #8b5cf6;
+    color: #8b5cf6;
+}
+"""
+
+    @staticmethod
+    def get_html() -> str:
+        return """
+<div class="widget-matrix" data-widget-id="matrix">
+    <div class="widget-header">
+        <div class="widget-title">
+            <span class="widget-icon">&#128172;</span>
+            <span>Matrix-Chat</span>
+        </div>
+        <button class="widget-settings-btn" onclick="openWidgetSettings('matrix')" title="Einstellungen">&#9881;</button>
+    </div>
+    <div class="matrix-list" id="matrix-list">
+        <!-- Wird dynamisch gefuellt -->
+    </div>
+    <div class="matrix-footer">
+        <button class="matrix-all-btn" onclick="openMessenger()">+ Messenger oeffnen</button>
+    </div>
+</div>
+"""
+
+    @staticmethod
+    def get_js() -> str:
+        return """
+// ===== Matrix Widget JavaScript =====
+
+function getDefaultMatrixChats() {
+    const now = Date.now();
+    return [
+        {
+            id: 'room1',
+            room: 'Kollegium Deutsch',
+            lastMessage: 'Hat jemand das neue Curriculum?',
+            sender: 'Fr. Becker',
+            time: new Date(now - 30 * 60 * 1000).toISOString(),
+            unread: true
+        },
+        {
+            id: 'room2',
+            room: 'Klassenfahrt 10a',
+            lastMessage: 'Die Anmeldungen sind komplett!',
+            sender: 'Hr. Klein',
+            time: new Date(now - 3 * 60 * 60 * 1000).toISOString(),
+            unread: false
+        },
+        {
+            id: 'room3',
+            room: 'Fachschaft',
+            lastMessage: 'Termin fuer naechste Sitzung...',
+            sender: 'Sie',
+            time: new Date(now - 24 * 60 * 60 * 1000).toISOString(),
+            unread: false
+        }
+    ];
+}
+
+function formatMatrixTime(timeStr) {
+    const time = new Date(timeStr);
+    const now = new Date();
+    const diffMs = now - time;
+    const diffMins = Math.floor(diffMs / (60 * 1000));
+    const diffHours = Math.floor(diffMs / (60 * 60 * 1000));
+
+    if (diffMins < 1) return 'jetzt';
+    if (diffMins < 60) return `${diffMins}m`;
+    if (diffHours < 24) return `${diffHours}h`;
+    return time.toLocaleDateString('de-DE', { day: '2-digit', month: '2-digit' });
+}
+
+function renderMatrixChats() {
+    const list = document.getElementById('matrix-list');
+    if (!list) return;
+
+    const chats = getDefaultMatrixChats();
+
+    if (chats.length === 0) {
+        list.innerHTML = `
+            <div class="matrix-empty">
+                <div class="matrix-empty-icon">&#128172;</div>
+                <div>Keine Chats verfuegbar</div>
+            </div>
+        `;
+        return;
+    }
+
+    list.innerHTML = chats.map(chat => `
+        <div class="chat-item" onclick="openMatrixRoom('${chat.id}')">
+            <div class="chat-avatar">&#128172;</div>
+            <div class="chat-content">
+                <div class="chat-header">
+                    <span class="chat-room">${chat.room}</span>
+                    <span class="chat-time">${formatMatrixTime(chat.time)}</span>
+                </div>
+                <div class="chat-message">${chat.sender}: ${chat.lastMessage}</div>
+            </div>
+            ${chat.unread ? '<div class="chat-unread"></div>' : ''}
+        </div>
+    `).join('');
+}
+
+function openMatrixRoom(roomId) {
+    if (typeof loadModule === 'function') {
+        loadModule('messenger');
+        console.log('Opening room:', roomId);
+    }
+}
+
+function openMessenger() {
+    if (typeof loadModule === 'function') {
+        loadModule('messenger');
+    }
+}
+
+function initMatrixWidget() {
+    renderMatrixChats();
+}
+"""