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/ai_processor/utils.py

@@ -0,0 +1,83 @@
+"""
+AI Processor - Utility Functions
+
+Image encoding and helper functions.
+"""
+
+from pathlib import Path
+import base64
+import shutil
+import logging
+
+from .config import BEREINIGT_DIR
+
+logger = logging.getLogger(__name__)
+
+
+def encode_image_to_data_url(input_path: Path) -> str:
+    """
+    Encode an image file to a data URL for API requests.
+
+    Args:
+        input_path: Path to the image file
+
+    Returns:
+        Data URL string (data:image/jpeg;base64,...)
+    """
+    image_bytes = input_path.read_bytes()
+    image_b64 = base64.b64encode(image_bytes).decode("utf-8")
+    return f"data:image/jpeg;base64,{image_b64}"
+
+
+def encode_image_to_base64(input_path: Path) -> str:
+    """
+    Encode an image file to base64 string.
+
+    Args:
+        input_path: Path to the image file
+
+    Returns:
+        Base64 encoded string
+    """
+    image_bytes = input_path.read_bytes()
+    return base64.b64encode(image_bytes).decode("utf-8")
+
+
+def dummy_process_scan(input_path: Path) -> Path:
+    """
+    Simple copy to Bereinigt folder - kept as fallback.
+
+    Args:
+        input_path: Path to input file
+
+    Returns:
+        Path to copied file
+    """
+    if not input_path.exists():
+        raise FileNotFoundError(f"Eingabedatei nicht gefunden: {input_path}")
+    new_name = input_path.stem + "_bereinigt" + input_path.suffix
+    target = BEREINIGT_DIR / new_name
+    shutil.copy2(input_path, target)
+    return target
+
+
+def get_media_type(input_path: Path) -> str:
+    """
+    Determine media type from file extension.
+
+    Args:
+        input_path: Path to the file
+
+    Returns:
+        MIME type string
+    """
+    suffix = input_path.suffix.lower()
+    media_types = {
+        ".jpg": "image/jpeg",
+        ".jpeg": "image/jpeg",
+        ".png": "image/png",
+        ".gif": "image/gif",
+        ".webp": "image/webp",
+        ".pdf": "application/pdf",
+    }
+    return media_types.get(suffix, "image/jpeg")