📈(summary) kickstart analytics tracking in summary microservice

Add product analytics to understand summary feature usage and behavior.
Track transcript and task metadata for insights without exposing sensitive
content or speaker data.

Hacky but functional PostHog usage - fully optional for self-hosting.
Extensive tracking approach works for current needs despite not being
PostHog's typical use case.

src/summary/summary/api/route/tasks.py

@@ -1,5 +1,6 @@
 """API routes related to application tasks."""
 
+import time
 from typing import Optional
 
 from celery.result import AsyncResult
@@ -33,7 +34,7 @@ async def create_task(request: TaskCreation):
         )
     else:
         task = process_audio_transcribe_summarize_v2.delay(
-            request.filename, request.email, request.sub
+            request.filename, request.email, request.sub, time.time()
         )
 
     return {"id": task.id, "message": "Task created"}