Reduce all command timeouts to 2-3 seconds max

With 10-second host heartbeat timeout, all command timeouts must be significantly lower to ensure total collection time stays under 10 seconds.

Changed timeouts:
- smartctl: 10s → 3s (critical: multiple drives queried sequentially)
- du: 5s → 2s
- lsblk: 5s → 2s
- systemctl list commands: 5s → 3s
- systemctl show/is-active: 3s → 2s
- docker commands: 5s → 3s
- df, ip commands: 3s → 2s

Total worst-case collection time now capped at more reasonable levels, preventing false host offline alerts from blocking operations.

Cargo.lock

@@ -279,7 +279,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.186"
+version = "0.1.187"
 dependencies = [
  "anyhow",
  "chrono",
@@ -301,7 +301,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.186"
+version = "0.1.187"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -324,7 +324,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.186"
+version = "0.1.187"
 dependencies = [
  "chrono",
  "serde",