Implement WakeOnLAN functionality with simplified configuration

- Add Status::Offline enum variant for disconnected hosts
- All configured hosts now always visible showing offline status when disconnected
- Add WakeOnLAN support using wake-on-lan Rust crate
- Implement w key binding to wake offline hosts with MAC addresses
- Simplify configuration to single [hosts] section with MAC addresses only
- Change critical status icon from ◯ to ! for better visibility
- Add proper MAC address parsing and error handling
- Silent WakeOnLAN operation with logging for success/failure

Configuration format:
[hosts]
hostname = { mac_address = "AA:BB:CC:DD:EE:FF" }

Cargo.lock

@@ -270,7 +270,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.52"
+version = "0.1.54"
 dependencies = [
  "anyhow",
  "chrono",
@@ -286,12 +286,13 @@ dependencies = [
  "toml",
  "tracing",
  "tracing-subscriber",
+ "wake-on-lan",
  "zmq",
 ]
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.52"
+version = "0.1.54"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -314,7 +315,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.52"
+version = "0.1.54"
 dependencies = [
  "chrono",
  "serde",
@@ -2064,6 +2065,12 @@ version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
 
+[[package]]
+name = "wake-on-lan"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ccf60b60ad7e5b1b37372c5134cbcab4db0706c231d212e0c643a077462bc8f"
+
 [[package]]
 name = "walkdir"
 version = "2.5.0"