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.ini

@@ -0,0 +1,72 @@
+# Alembic Configuration fuer Classroom Engine (Feature f15)
+#
+# Migration-Tool fuer PostgreSQL Schema-Aenderungen.
+
+[alembic]
+# Pfad zum migrations-Verzeichnis
+script_location = alembic
+
+# Template fuer neue Migrationen
+file_template = %%(year)d%%(month).2d%%(day).2d_%%(hour).2d%%(minute).2d_%%(rev)s_%%(slug)s
+
+# Prepend sys.path
+prepend_sys_path = .
+
+# Timezone fuer Revisions
+timezone = UTC
+
+# Truncate slug
+truncate_slug_length = 40
+
+# Version locations
+version_locations = %(here)s/alembic/versions
+
+# Output encoding
+output_encoding = utf-8
+
+# Database URL (wird von env.py ueberschrieben)
+sqlalchemy.url = postgresql://breakpilot:breakpilot123@localhost:5432/breakpilot
+
+
+[post_write_hooks]
+# Formatierung nach Migration-Erstellung
+# hooks = black
+# black.type = console_scripts
+# black.entrypoint = black
+# black.options = -q
+
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S