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/ffmpeg_service.py

@@ -0,0 +1,49 @@
+import subprocess
+import os
+import logging
+from ..config import settings
+
+logger = logging.getLogger(__name__)
+
+class FFmpegService:
+    def split_audio(self, input_path: str, meeting_id: int) -> list:
+        """
+        Splits audio into 30min chunks using ffmpeg segment muxer.
+        Returns a list of paths to the created chunks.
+        """
+        output_dir = os.path.join(settings.UPLOAD_DIR, "chunks", str(meeting_id))
+        os.makedirs(output_dir, exist_ok=True)
+        
+        output_pattern = os.path.join(output_dir, "chunk_%03d.mp3")
+        
+        # ffmpeg -i input.mp3 -f segment -segment_time 1800 -c copy chunk_%03d.mp3
+        cmd = [
+            "ffmpeg", "-i", input_path,
+            "-f", "segment",
+            "-segment_time", str(settings.CHUNK_DURATION_SEC),
+            "-c", "copy",
+            output_pattern
+        ]
+        
+        logger.info(f"Splitting {input_path} into segments...")
+        result = subprocess.run(cmd, capture_output=True, text=True)
+        
+        if result.returncode != 0:
+            logger.error(f"FFmpeg Error: {result.stderr}")
+            raise Exception("Failed to split audio file.")
+            
+        chunks = sorted([os.path.join(output_dir, f) for f in os.listdir(output_dir) if f.endswith(".mp3")])
+        logger.info(f"Created {len(chunks)} chunks.")
+        return chunks
+
+    def get_duration(self, input_path: str) -> float:
+        """Gets duration of audio file in seconds."""
+        cmd = [
+            "ffprobe", "-v", "error", "-show_entries", "format=duration",
+            "-of", "default=noprint_wrappers=1:nokey=1", input_path
+        ]
+        result = subprocess.run(cmd, capture_output=True, text=True)
+        try:
+            return float(result.stdout.strip())
+        except:
+            return 0.0