Fix heartbeat detection to properly detect offline hosts

- Add independent heartbeat checking timer (1 second interval) separate from metric reception
- Move get_connected_hosts() call outside metric receive condition to run periodically
- Remove duplicate update_hosts() call from metric processing to avoid redundancy
- Ensure offline host detection works even when no new metrics are received
- Fix issue where hosts going offline were never detected due to conditional heartbeat check
- Heartbeat timeouts now properly detected within configured timeout + 1 second
- Bump version to 0.1.62

Cargo.lock

@@ -270,7 +270,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.60"
+version = "0.1.61"
 dependencies = [
  "anyhow",
  "chrono",
@@ -292,7 +292,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.60"
+version = "0.1.61"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -315,7 +315,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.60"
+version = "0.1.61"
 dependencies = [
  "chrono",
  "serde",