add configuration profiles with per-invocation --profile flag

- Add SystemPrompt field to HushConfig (empty = built-in default)
- Refactor ConfigManager: extract ApplyTomlFields, add LoadWithProfile(),
  ListProfiles(), GetProfilePath(), EnsureProfilesDirExists(); remove
  HUSH_PROFILE env-var logic (profiles are now resolved by the CLI)
- Extend socket protocol: action commands (START/STOP/TOGGLE/ABORT) now
  carry a [4-byte LE length][optional HushConfig JSON] payload so the CLI
  can pass a per-invocation config override without restarting the daemon
- Add GENERATE_PROFILE (cmd 7) socket command: CLI sends a description,
  daemon calls the LLM and returns a generated system prompt
- Orchestrator: StopAndProcessAsync accepts optional HushConfig override;
  ProcessWithLlmAsync uses proper system/user chat roles and respects
  config.SystemPrompt; add GenerateProfilePromptAsync
- Split CompleteTextAsync signature to (systemPrompt, userMessage, model)
  across ITextStreamingProvider, GroqProvider, FireworksProvider
- Add --profile/-p flag to hush toggle and hush stop
- Add hush profiles subcommand: list, get, new (manual or AI-generated), edit

Hush.Cli/src/SocketClient.cs

@@ -1,6 +1,8 @@
 using System.Net.Sockets;
 using System.Text;
 using System.Text.Json;
+using System.Text.Json.Serialization.Metadata;
+using Hush.Config;
 using Hush.Daemon;
 
 namespace Hush.Cli;
@@ -15,7 +17,7 @@ public class SocketClient : IAsyncDisposable
         var runtimeDir = Environment.GetEnvironmentVariable("XDG_RUNTIME_DIR");
         var baseDir = string.IsNullOrEmpty(runtimeDir) ? Path.GetTempPath() : runtimeDir;
         var socketPath = Path.Combine(baseDir, "hush.sock");
-        
+
         _endPoint = new UnixDomainSocketEndPoint(socketPath);
         _socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.Unspecified);
     }
@@ -26,9 +28,58 @@ public class SocketClient : IAsyncDisposable
         await _socket.ConnectAsync(_endPoint, cts.Token);
     }
 
+    /// <summary>
+    /// Sends a command with no config payload.
+    /// Action commands (START/STOP/TOGGLE/ABORT) always include a 4-byte zero length prefix
+    /// so the daemon can read the same framing unconditionally.
+    /// </summary>
     public async Task SendCommandAsync(byte command)
     {
-        await _socket.SendAsync(new[] { command }, SocketFlags.None);
+        if (IsActionCommand(command))
+        {
+            // [cmd][4 zero bytes] — signals no config override
+            var frame = new byte[5];
+            frame[0] = command;
+            await _socket.SendAsync(frame, SocketFlags.None);
+        }
+        else
+        {
+            await _socket.SendAsync(new[] { command }, SocketFlags.None);
+        }
+    }
+
+    /// <summary>
+    /// Sends an action command with a HushConfig override payload.
+    /// Format: [1 byte cmd][4-byte LE length][N bytes JSON]
+    /// </summary>
+    public async Task SendCommandWithConfigAsync(byte command, HushConfig config)
+    {
+        var jsonBytes = JsonSerializer.SerializeToUtf8Bytes(config, HushConfigContext.Default.HushConfig);
+        var lenBytes  = BitConverter.GetBytes(jsonBytes.Length);
+
+        var frame = new byte[1 + 4 + jsonBytes.Length];
+        frame[0] = command;
+        lenBytes.CopyTo(frame, 1);
+        jsonBytes.CopyTo(frame, 5);
+
+        await _socket.SendAsync(frame, SocketFlags.None);
+    }
+
+    /// <summary>
+    /// Sends a request with a typed JSON payload (e.g. GENERATE_PROFILE).
+    /// Format: [1 byte cmd][4-byte LE length][N bytes JSON]
+    /// </summary>
+    public async Task SendRequestAsync<TRequest>(byte command, TRequest payload, JsonTypeInfo<TRequest> typeInfo)
+    {
+        var jsonBytes = JsonSerializer.SerializeToUtf8Bytes(payload, typeInfo);
+        var lenBytes  = BitConverter.GetBytes(jsonBytes.Length);
+
+        var frame = new byte[1 + 4 + jsonBytes.Length];
+        frame[0] = command;
+        lenBytes.CopyTo(frame, 1);
+        jsonBytes.CopyTo(frame, 5);
+
+        await _socket.SendAsync(frame, SocketFlags.None);
     }
 
     public async Task<T?> ReceiveJsonAsync<T>(TimeSpan timeout)
@@ -36,10 +87,10 @@ public class SocketClient : IAsyncDisposable
         var cts = new CancellationTokenSource(timeout);
         var buffer = new byte[4096];
         var bytesRead = await _socket.ReceiveAsync(buffer, SocketFlags.None, cts.Token);
-        
+
         if (bytesRead == 0)
             return default;
-        
+
         var json = Encoding.UTF8.GetString(buffer, 0, bytesRead);
         return (T?)JsonSerializer.Deserialize(json, typeof(T), DaemonJsonContext.Default);
     }
@@ -61,4 +112,8 @@ public class SocketClient : IAsyncDisposable
         _socket.Dispose();
         await ValueTask.CompletedTask;
     }
+
+    private static bool IsActionCommand(byte command) =>
+        command is DaemonProtocol.START or DaemonProtocol.STOP
+                or DaemonProtocol.ABORT or DaemonProtocol.TOGGLE;
 }