feat: Introduce Summary and Professional skills, replacing the old style mode and text structuring configuration options.

Core/Skills/SummarySkill.cs

@@ -0,0 +1,25 @@
+namespace Toak.Core.Skills;
+
+public class SummarySkill : ISkill
+{
+    public string Name => "Summary";
+    public string Description => "Summarizes the spoken text securely and concisely, removing fluff.";
+    public string[] Hotwords => new[] { "System summary", "System summarize", "System concise" };
+
+    public bool HandlesExecution => false;
+
+    public string GetSystemPrompt(string rawTranscript)
+    {
+        return @"You are an expert editor who strips all fluff and makes text as concise as possible.
+The user wants to summarize the following text. The transcript might start with a hotword like 'System summary'.
+- Strip all fluff, filler, and unnecessary conversational words.
+- Make the output as direct and brief as possible without losing the core information.
+- Use clear, crisp phrasing. If the text lists items or instructions, format them logically.
+- Output ONLY the final summarized text. Do not include markdown, explanations, or quotes.";
+    }
+
+    public void Execute(string llmResult)
+    {
+        // Not used since HandlesExecution is false
+    }
+}