feat(transcription): add meeting assistant micro-service v0.1.0

- Added FastAPI backend with FFmpeg and Gemini 2.0 integration
- Added React frontend with upload and meeting list
- Integrated into main docker-compose stack and dashboard

transcription-tool/backend/services/transcription_service.py

@@ -0,0 +1,58 @@
+import os
+import time
+import logging
+from google import genai
+from google.genai import types
+from ..config import settings
+
+logger = logging.getLogger(__name__)
+
+class TranscriptionService:
+    def __init__(self):
+        if not settings.GEMINI_API_KEY:
+            raise Exception("Gemini API Key missing.")
+        self.client = genai.Client(api_key=settings.GEMINI_API_KEY)
+
+    def transcribe_chunk(self, file_path: str, offset_seconds: int = 0) -> dict:
+        """
+        Uploads a chunk to Gemini and returns the transcription with timestamps.
+        """
+        logger.info(f"Uploading chunk {file_path} to Gemini...")
+        
+        # 1. Upload file
+        media_file = self.client.files.upload(path=file_path)
+        
+        # 2. Wait for processing (usually fast for audio)
+        while media_file.state == "PROCESSING":
+            time.sleep(2)
+            media_file = self.client.files.get(name=media_file.name)
+            
+        if media_file.state == "FAILED":
+            raise Exception("File processing failed at Gemini.")
+
+        # 3. Transcribe with Diarization and Timestamps
+        prompt = """
+        Transkribiere dieses Audio wortgetreu. 
+        Identifiziere die Sprecher (Sprecher A, Sprecher B, etc.).
+        Gib das Ergebnis als strukturierte Liste mit Timestamps aus.
+        Wichtig: Das Audio ist ein Teil eines größeren Gesprächs. 
+        Antworte NUR mit dem Transkript im Format:
+        [MM:SS] Sprecher X: Text
+        """
+        
+        logger.info(f"Generating transcription for {file_path}...")
+        response = self.client.models.generate_content(
+            model="gemini-2.0-flash",
+            contents=[media_file, prompt],
+            config=types.GenerateContentConfig(
+                temperature=0.1, # Low temp for accuracy
+            )
+        )
+
+        # Cleanup: Delete file from Gemini storage
+        self.client.files.delete(name=media_file.name)
+
+        return {
+            "raw_text": response.text,
+            "offset": offset_seconds
+        }