fix(path-type): NaN-safe bracket clamping (f64::clamp panics on a NaN path length)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/compose/src/lib.rs

@@ -417,7 +417,7 @@ pub fn frame_specs(doc: &Document, sid: StoryId) -> Vec<FrameSpec> {
                     path: None,
                     ..tf.options.clone()
                 };
-                let end = pt.end.map_or(len, |e| e.clamp(0.0, len));
+                let end = pt.end.map_or(len, |e| e.max(0.0).min(len));
                 (Rect::new(0.0, 0.0, (end - pt.start).max(1.0), size * 1.6), opts)
             }
             None => (item.text_area(), tf.options.clone()),

crates/engine/src/cmd/path_type.rs

@@ -97,7 +97,7 @@ fn path_options(s: &mut Session, p: &Value) -> Result<Value> {
             return Ok(json!({"deleted": true}));
         }
         if let Some(v) = p.get("start").and_then(Value::as_f64).filter(|v| v.is_finite()) {
-            pt.start = v.clamp(0.0, len);
+            pt.start = v.max(0.0).min(len);
         }
         match p.get("end") {
             Some(Value::Null) => pt.end = None,