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/alembic/versions/20260115_1900_006_teacher_feedback.py

@@ -0,0 +1,45 @@
+"""Add teacher_feedback table for Phase 7.
+
+Revision ID: 006_teacher_feedback
+Revises: 005_lesson_reflections
+Create Date: 2026-01-15 19:00:00.000000
+"""
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers
+revision = '006_teacher_feedback'
+down_revision = '005_lesson_reflections'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    """Create teacher_feedback table."""
+    op.create_table(
+        'teacher_feedback',
+        sa.Column('id', sa.String(36), primary_key=True),
+        sa.Column('teacher_id', sa.String(100), nullable=False, index=True),
+        sa.Column('teacher_name', sa.String(200), default=''),
+        sa.Column('teacher_email', sa.String(200), default=''),
+        sa.Column('title', sa.String(500), nullable=False),
+        sa.Column('description', sa.Text, nullable=False),
+        sa.Column('feedback_type', sa.String(50), nullable=False, default='improvement'),
+        sa.Column('priority', sa.String(50), nullable=False, default='medium'),
+        sa.Column('status', sa.String(50), nullable=False, default='new', index=True),
+        sa.Column('related_feature', sa.String(50), nullable=True),
+        sa.Column('context_url', sa.String(500), default=''),
+        sa.Column('context_phase', sa.String(50), default=''),
+        sa.Column('context_session_id', sa.String(36), nullable=True),
+        sa.Column('user_agent', sa.String(500), default=''),
+        sa.Column('response', sa.Text, default=''),
+        sa.Column('responded_at', sa.DateTime, nullable=True),
+        sa.Column('responded_by', sa.String(100), nullable=True),
+        sa.Column('created_at', sa.DateTime, default=sa.func.now()),
+        sa.Column('updated_at', sa.DateTime, default=sa.func.now(), onupdate=sa.func.now()),
+    )
+
+
+def downgrade() -> None:
+    """Drop teacher_feedback table."""
+    op.drop_table('teacher_feedback')