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/secret_store/__init__.py

@@ -0,0 +1,34 @@
+"""
+BreakPilot Secret Store Module
+
+This module provides a unified interface for accessing secrets from:
+1. HashiCorp Vault (production)
+2. Environment variables (development fallback)
+3. Docker secrets (containerized environments)
+
+Security Architecture:
+- Vault is the primary secrets store in production
+- Environment variables serve as fallback for development
+- No secrets are ever hardcoded in the application code
+
+Note: Renamed from 'secrets' to 'secret_store' to avoid conflict
+with Python's built-in secrets module.
+"""
+
+from .vault_client import (
+    SecretsManager,
+    get_secrets_manager,
+    get_secret,
+    VaultConfig,
+    SecretNotFoundError,
+    VaultConnectionError,
+)
+
+__all__ = [
+    "SecretsManager",
+    "get_secrets_manager",
+    "get_secret",
+    "VaultConfig",
+    "SecretNotFoundError",
+    "VaultConnectionError",
+]