feat: collapsible tool lines in terminal

Long tool messages (e.g. Bash commands) are now stored in full and
displayed collapsed by default, with a toggle button to expand/collapse.
Removes backend truncation of Bash commands at 50 chars.

src-tauri/src/wsl_bridge.rs

@@ -1689,12 +1689,7 @@ fn format_tool_description(name: &str, input: &serde_json::Value) -> String {
         }
         "Bash" => {
             if let Some(cmd) = input.get("command").and_then(|v| v.as_str()) {
-                let truncated = if cmd.len() > 50 {
-                    format!("{}...", &cmd[..50])
-                } else {
-                    cmd.to_string()
-                };
-                format!("Running: {}", truncated)
+                format!("Running: {}", cmd)
             } else {
                 "Running command...".to_string()
             }
@@ -1855,9 +1850,7 @@ mod tests {
         let long_cmd = "a".repeat(100);
         let input = serde_json::json!({"command": long_cmd});
         let desc = format_tool_description("Bash", &input);
-        assert!(desc.starts_with("Running: "));
-        assert!(desc.ends_with("..."));
-        assert!(desc.len() < 70);
+        assert_eq!(desc, format!("Running: {}", long_cmd));
     }
 
     #[test]