feat: pick sketch profiles by their bounding curve ids so features keep the same region when parameters move the geometry, matching curves cut into pieces, refusing ambiguous or missing picks instead of taking another region, and storing point picks by curves

crates/doc/src/document.rs

@@ -76,8 +76,10 @@ pub enum ProfileSel {
     All,
     /// Profiles by index in the solved sketch's profile list.
     Indices { indices: Vec<usize> },
-    /// Profiles whose outer loop is made of exactly these curves (order-insensitive); stable
-    /// across parameter changes.
+    /// Profiles whose outer loop is made of exactly these curves, or pieces of them where other
+    /// curves cut them (order and repeats don't matter; see `sketch::profile_by_curves`). Found
+    /// again on every evaluation, so stable across parameter changes; no match or several is
+    /// an error, never another profile.
     Curves { loops: Vec<Vec<String>> },
     /// The profile containing each sketch point.
     Points { points: Vec<Vec2> },