Shell Outside and Both (walls grown out of the faces, or half out and half in: an offset body less a cavity) and tangent-chain face selection (open faces joined smoothly to the picked ones, by the surface normals either side of each edge)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/doc/src/document.rs

@@ -321,6 +321,12 @@ pub enum FeatureKind {
         thickness: String,
         #[serde(default, skip_serializing_if = "Option::is_none")]
         body: Option<String>,
+        /// inside (default) | outside | both (the wall straddles the faces).
+        #[serde(default, skip_serializing_if = "String::is_empty")]
+        direction: String,
+        /// Open the faces smoothly joined to the picked ones too.
+        #[serde(default, skip_serializing_if = "std::ops::Not::not")]
+        tangent_chain: bool,
     },
     /// Tilt faces (at the given points) about a neutral plane, leaning toward `pull`.
     Draft {