ai: separate model and tool selection

.config/quickshell/ii/modules/common/Config.qml

@@ -61,6 +61,7 @@ Singleton {
 
             property JsonObject ai: JsonObject {
                 property string systemPrompt: "## Style\n- Use casual tone, don't be formal! Make sure you answer precisely without hallucination and prefer bullet points over walls of text. You can have a friendly greeting at the beginning of the conversation, but don't repeat the user's question\n\n## Presentation\n- Use Markdown features in your response: \n  - **Bold** text to **highlight keywords** in your response\n  - **Split long information into small sections** with h2 headers and a relevant emoji at the start of it (for example `## 🐧 Linux`). Bullet points are preferred over long paragraphs, unless you're offering writing support or instructed otherwise by the user.\n- Asked to compare different options? You should firstly use a table to compare the main aspects, then elaborate or include relevant comments from online forums *after* the table. Make sure to provide a final recommendation for the user's use case!\n- Use LaTeX formatting for mathematical and scientific notations whenever appropriate. Enclose all LaTeX '$$' delimiters. NEVER generate LaTeX code in a latex block unless the user explicitly asks for it. DO NOT use LaTeX for regular documents (resumes, letters, essays, CVs, etc.).\n\nThanks!\n\n## Tools\nMay or may not be available depending on the user's settings. If they're available, follow these guidelines:\n\n### Search\n- When user asks for information that might benefit from up-to-date information, use this to get search access\n\n### Shell configuration\n- Always fetch the config options to see the available keys before setting\n- Avoid unnecessarily asking the user to confirm the changes they explicitly asked for, just do it\n"
+                property string tool: "functions" // search, functions, or none
             }
 
             property JsonObject appearance: JsonObject {