v0.3: PTT hotkey capture, mouse support, model params

- Replace PTT key dropdown with live key-capture textbox
- Use low-level keyboard hook for capture (distinguishes Left/Right Ctrl)
- Support mouse buttons as PTT (Left/Right/Middle/X1/X2 via WH_MOUSE_LL)
- Filter mouse clicks from capture, allow Left/Right Ctrl
- Add Noise/Speed/NoiseW sliders with live labels, reinit on MouseUp
- Stream audio via BufferedWaveProvider (no temp WAV files)
- Add text input field with Speak button
- Fix sentence terminator, UTF-8 marshaling, voice catalogue JSON

Robovoice.App/MainForm.Designer.cs

@@ -6,7 +6,7 @@ partial class MainForm
     private System.ComponentModel.IContainer? components = null;
 
     private Label lblPttKey = null!;
-    private ComboBox cmbPttKey = null!;
+    private TextBox txtPttKey = null!;
     private Label lblVoice = null!;
     private ComboBox cmbVoice = null!;
     private Button btnTestVoice = null!;
@@ -45,7 +45,7 @@ partial class MainForm
         components = new System.ComponentModel.Container();
 
         lblPttKey = new Label();
-        cmbPttKey = new ComboBox();
+        txtPttKey = new TextBox();
         lblVoice = new Label();
         cmbVoice = new ComboBox();
         btnTestVoice = new Button();
@@ -80,10 +80,11 @@ partial class MainForm
         lblPttKey.Size = new Size(60, 23);
         lblPttKey.TextAlign = ContentAlignment.MiddleLeft;
 
-        // cmbPttKey
-        cmbPttKey.Location = new Point(75, 12);
-        cmbPttKey.Size = new Size(80, 23);
-        cmbPttKey.DropDownStyle = ComboBoxStyle.DropDownList;
+        // txtPttKey
+        txtPttKey.Location = new Point(75, 12);
+        txtPttKey.Size = new Size(80, 23);
+        txtPttKey.ReadOnly = true;
+        txtPttKey.TextAlign = HorizontalAlignment.Center;
 
         // lblVoice
         lblVoice.Text = "Voice:";
@@ -249,7 +250,7 @@ partial class MainForm
         AutoScaleMode = AutoScaleMode.Font;
         ClientSize = new Size(824, 509);
         Controls.Add(lblPttKey);
-        Controls.Add(cmbPttKey);
+        Controls.Add(txtPttKey);
         Controls.Add(lblVoice);
         Controls.Add(cmbVoice);
         Controls.Add(btnTestVoice);