Add uptime field to detailed health check endpoint

- Added uptime field to DetailedHealthStatus model
- Calculate uptime as time since startup
- Removed obsolete task entries from Docs/tasks.md

src/server/api/health.py

@@ -69,6 +69,7 @@ class DetailedHealthStatus(BaseModel):
     version: str = APP_VERSION
     dependencies: DependencyHealth
     startup_time: datetime
+    uptime: str
 
 
 # Global startup time
@@ -298,11 +299,16 @@ async def detailed_health_check(
             system=system_metrics,
         )
 
+        # Calculate uptime
+        uptime_delta = datetime.now() - startup_time
+        uptime_str = str(uptime_delta).split('.')[0]  # Remove microseconds
+
         return DetailedHealthStatus(
             status=overall_status,
             timestamp=datetime.now().isoformat(),
             dependencies=dependencies,
             startup_time=startup_time,
+            uptime=uptime_str,
         )
     except Exception as e:
         logger.error("Detailed health check failed: %s", e)