Add torrent statistics to transmission-vpn service

Implement aggregate torrent statistics display for transmission-vpn service
via Transmission RPC API. Shows active torrent count and total download/upload
speeds. Change VPN route label from "ip:" to "route:" for clarity.

- Add get_transmission_stats() method to query Transmission RPC
- Display format: "X active, ↓ MB/s, ↑ MB/s"
- Update version to v0.1.244

Cargo.lock

@@ -279,7 +279,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.242"
+version = "0.1.243"
 dependencies = [
  "anyhow",
  "chrono",
@@ -301,7 +301,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.242"
+version = "0.1.243"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -325,7 +325,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.242"
+version = "0.1.243"
 dependencies = [
  "chrono",
  "serde",