fix: UTF-8 Panic bei String-Truncation (db.rs + knowledge.rs) [appimage]

Crash: "byte index 200 is not a char boundary; inside '─' (bytes 198..201)"
Fix: char_indices() statt byte-slice für sicheres Abschneiden bei
Multi-Byte-Zeichen (ä, ü, ─, etc.)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src-tauri/src/db.rs

@@ -717,7 +717,13 @@ impl Database {
         let mut summary_parts: Vec<String> = Vec::new();
         for (_, role, content) in &old_messages {
             let preview = if content.len() > 200 {
-                format!("{}...", &content[..200])
+                // Sicher an Char-Boundary abschneiden (Multi-Byte wie ─, ä, ü)
+                let end = content.char_indices()
+                    .take_while(|(i, _)| *i < 200)
+                    .last()
+                    .map(|(i, c)| i + c.len_utf8())
+                    .unwrap_or(200.min(content.len()));
+                format!("{}...", &content[..end])
             } else {
                 content.clone()
             };

src-tauri/src/knowledge.rs

@@ -993,9 +993,14 @@ pub async fn format_tool_hints(
 
     for entry in entries {
         hints.push(format!("\n**{}** ({})", entry.title, entry.category));
-        // Content auf ~300 Zeichen kürzen
+        // Content auf ~300 Zeichen kürzen (sicher an Char-Boundary)
         let content = if entry.content.len() > 300 {
-            format!("{}...", &entry.content[..300])
+            let end = entry.content.char_indices()
+                .take_while(|(i, _)| *i < 300)
+                .last()
+                .map(|(i, c)| i + c.len_utf8())
+                .unwrap_or(300.min(entry.content.len()));
+            format!("{}...", &entry.content[..end])
         } else {
             entry.content
         };

src-tauri/src/voice.rs

@@ -49,33 +49,58 @@ fn whisper_model_path() -> String {
         })
 }
 
+/// Verfügbare Piper-Modelle mit Dateinamen
+const PIPER_VOICES: &[(&str, &str)] = &[
+    ("kerstin",          "de_DE-kerstin-low.onnx"),
+    ("thorsten-high",    "de_DE-thorsten-high.onnx"),
+    ("thorsten",         "de_DE-thorsten-medium.onnx"),
+    ("eva",              "de_DE-eva_k-x_low.onnx"),
+    ("ramona",           "de_DE-ramona-low.onnx"),
+];
+
+/// Standard-Stimme: Kerstin (weiblich, deutsch)
+const DEFAULT_VOICE: &str = "kerstin";
+
 fn piper_model_path() -> String {
-    std::env::var("PIPER_MODEL")
+    piper_model_for_voice(None)
-        .unwrap_or_else(|_| {
+}
-            let exe_dir = std::env::current_exe()
-                .ok()
-                .and_then(|p| p.parent().map(|p| p.to_path_buf()));
 
-            let home_dir = std::env::var("HOME").ok()
+/// Modell-Pfad für eine bestimmte Stimme (oder Default)
-                .map(std::path::PathBuf::from);
+fn piper_model_for_voice(voice: Option<&str>) -> String {
+    // Env-Override hat Vorrang
+    if let Ok(path) = std::env::var("PIPER_MODEL") {
+        return path;
+    }
 
-            let candidates = vec![
+    let voice_id = voice.unwrap_or(DEFAULT_VOICE);
-                // Relativ zum Binary (Dev-Modus)
+    let filename = PIPER_VOICES.iter()
-                exe_dir.as_ref().map(|d| d.join("../models/de_DE-thorsten-high.onnx")),
+        .find(|(id, _)| *id == voice_id)
-                exe_dir.as_ref().map(|d| d.join("models/de_DE-thorsten-high.onnx")),
+        .map(|(_, f)| *f)
-                // XDG Data Home / Home-Verzeichnis (AppImage + Nix-Wrapper)
+        .unwrap_or(PIPER_VOICES[0].1); // Fallback auf Kerstin
-                home_dir.as_ref().map(|d| d.join(".local/share/claude-desktop/models/de_DE-thorsten-high.onnx")),
-                home_dir.as_ref().map(|d| d.join(".claude-desktop/models/de_DE-thorsten-high.onnx")),
-                // CWD Fallback
-                Some(std::path::PathBuf::from("models/de_DE-thorsten-high.onnx")),
-            ];
 
-            candidates.into_iter()
+    let exe_dir = std::env::current_exe()
-                .flatten()
+        .ok()
-                .find(|p| p.exists())
+        .and_then(|p| p.parent().map(|p| p.to_path_buf()));
-                .map(|p| p.to_string_lossy().to_string())
+
-                .unwrap_or_else(|| "models/de_DE-thorsten-high.onnx".to_string())
+    let home_dir = std::env::var("HOME").ok()
-        })
+        .map(std::path::PathBuf::from);
+
+    let candidates = vec![
+        // Relativ zum Binary (Dev-Modus)
+        exe_dir.as_ref().map(|d| d.join("../models").join(filename)),
+        exe_dir.as_ref().map(|d| d.join("models").join(filename)),
+        // XDG Data Home / Home-Verzeichnis (AppImage + Nix-Wrapper)
+        home_dir.as_ref().map(|d| d.join(".local/share/claude-desktop/models").join(filename)),
+        home_dir.as_ref().map(|d| d.join(".claude-desktop/models").join(filename)),
+        // CWD Fallback
+        Some(std::path::PathBuf::from("models").join(filename)),
+    ];
+
+    candidates.into_iter()
+        .flatten()
+        .find(|p| p.exists())
+        .map(|p| p.to_string_lossy().to_string())
+        .unwrap_or_else(|| format!("models/{}", filename))
 }
 
 /// Voice-System Status
@@ -227,9 +252,9 @@ pub async fn transcribe_audio(
 #[tauri::command]
 pub async fn text_to_speech(
     text: String,
-    _voice: Option<String>,  // Wird für Piper ignoriert (Modell bestimmt Stimme)
+    voice: Option<String>,
 ) -> Result<String, String> {
-    let model = piper_model_path();
+    let model = piper_model_for_voice(voice.as_deref());
 
     if !std::path::Path::new(&model).exists() {
         return Err(format!("Piper-Modell nicht gefunden: {}", model));
@@ -302,10 +327,28 @@ fn pcm_to_wav(pcm: &[u8], sample_rate: u32, channels: u16, bits_per_sample: u16)
     wav
 }
 
-/// Verfügbare TTS-Stimmen — bei Piper: Modell-basiert
+/// Verfügbare TTS-Stimmen — prüft welche Modelle lokal vorhanden sind
 #[tauri::command]
 pub async fn get_tts_voices() -> Result<Vec<serde_json::Value>, String> {
-    Ok(vec![
+    let voices_meta = vec![
-        serde_json::json!({ "id": "thorsten-high", "name": "Thorsten (Deutsch)", "description": "Lokal, hohe Qualität, männlich" }),
+        ("kerstin",       "Kerstin (Deutsch)",  "Weiblich, lokal, Standard"),
-    ])
+        ("thorsten-high", "Thorsten HQ (Deutsch)", "Männlich, hohe Qualität, lokal"),
+        ("thorsten",      "Thorsten (Deutsch)", "Männlich, mittlere Qualität, lokal"),
+        ("eva",           "Eva (Deutsch)",      "Weiblich, lokal"),
+        ("ramona",        "Ramona (Deutsch)",   "Weiblich, lokal"),
+    ];
+
+    let mut result = Vec::new();
+    for (id, name, desc) in voices_meta {
+        let model_path = piper_model_for_voice(Some(id));
+        let available = std::path::Path::new(&model_path).exists();
+        result.push(serde_json::json!({
+            "id": id,
+            "name": name,
+            "description": desc,
+            "available": available,
+            "default": id == DEFAULT_VOICE,
+        }));
+    }
+    Ok(result)
 }