Native-noden vastausten siivous: stop-sekvenssit + selitystekstien poisto

Stop-sekvenssit laajennettu: Please note, This is, Example, ```
strip_code_fences laajennettu poistamaan:
- Selitystekstit lopusta (Please note, This is a basic, Note that, ...)
- Johdantolauseet alusta (Sure!, Here is, Certainly!)
System prompt vahvistettu: "No 'Please note' or 'Here is' text"

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

network-poc/native-node/src/inference.rs

@@ -79,7 +79,7 @@ impl LlmEngine {
     }
 
     pub async fn generate(&self, prompt: &str, max_tokens: usize) -> Result<GenerateResult, String> {
-        let system = "You are a coding assistant. Respond with ONLY code. Use proper newlines and indentation. No explanations, no markdown fences, no comments unless asked.";
+        let system = "You are a coding assistant. Respond with ONLY code. No explanations, no markdown fences, no 'Please note' or 'Here is' text. Only working code with proper imports.";
         let model = self.model.borrow().clone();
 
         let start = Instant::now();
@@ -94,7 +94,7 @@ impl LlmEngine {
                     "temperature": 0.7,
                     "top_k": 40,
                     "repeat_penalty": 1.15,
-                    "stop": ["<|im_end|>", "\n###", "\nExplanation", "\nNote:"]
+                    "stop": ["<|im_end|>", "\n###", "\nExplanation", "\nNote:", "\nPlease note", "\nThis is", "\n```\n\n", "\n// Example", "\n# Example"]
                 }
             }))
             .send()
@@ -127,7 +127,7 @@ impl LlmEngine {
     }
 }
 
-/// Siivoa mahdolliset markdown-koodiblokki-merkit
+/// Siivoa markdown-koodiblokki-merkit ja selitystekstit
 fn strip_code_fences(text: &str) -> String {
     let mut result = text.trim().to_string();
 
@@ -147,7 +147,26 @@ fn strip_code_fences(text: &str) -> String {
         }
     }
 
-    result
+    // Poista selitysteksti lopusta (kaikki rivin "\nPlease note" jälkeen jne.)
+    let lower = result.to_lowercase();
+    for stop in &["\nplease note", "\nthis is a basic", "\nthis code", "\nnote that", "\nremember to", "\nyou can", "\nto run"] {
+        if let Some(pos) = lower.find(stop) {
+            result = result[..pos].trim_end().to_string();
+        }
+    }
+
+    // Poista johdantolauseet alusta
+    let lower = result.to_lowercase();
+    for prefix in &["sure!", "here is", "here's", "certainly!", "below is"] {
+        if lower.starts_with(prefix) {
+            if let Some(nl) = result.find('\n') {
+                result = result[nl + 1..].to_string();
+            }
+            break;
+        }
+    }
+
+    result.trim().to_string()
 }
 
 pub struct GenerateResult {