feat(select): offer the selection modes at "Select objects"

Only Previous and Last were on offer, so Window, Crossing, Fence, the two
polygons and All could not be reached at all -- and with no keyboard to
type them into, the buttons were the only way in.

Window and Crossing fix the sense of the next box. Dragging derives that
from the direction the corner travels and would overwrite it the moment
the corner moved, so the derivation stands down while a keyword holds it.
Add and Remove decide what a pick does for the rest of the round: Remove
subtracts the way Shift already does, rather than through PICKADD, which
decides whether a pick *replaces* the set and so would have wiped
everything gathered so far. Both are dropped when the next command
starts, since neither outlives the selection that asked for them.

Fence and the polygons are picked point by point, which TRIM and EXTEND
already ask for. That gesture -- the points, the rubber-banded dashed
preview, whether the path closes -- moves into one place both bind to,
and the two preview builders duplicated in trim.rs go with it.

A fence is not the polygon test with crossing set: that closes the point
list and counts whatever lies inside, so a line drawn past a row of
objects would take everything behind it too. It gets a hit test that only
counts a real intersection, and skips the area-based geometry entirely.

The lasso gathered its hits from wires, hatches, block hatches, meshes and
block meshes inline; the new modes need the same list, and a second copy
would drift. Both now come through `Scene::path_hit_handles`.

Closes #596

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/modules/draw/select.rs

@@ -13,6 +13,7 @@ use glam::DVec3;
 use crate::t;
 
 use crate::command::{CadCommand, CmdOption, CmdResult};
+use crate::modules::draw::fence::FencePick;
 use crate::scene::model::wire_model::WireModel;
 
 pub struct SelectObjectsCommand {
@@ -23,6 +24,13 @@ pub struct SelectObjectsCommand {
     /// When true, gathering continues until Enter / right-click commits the set.
     /// When false, the first completed selection action fires immediately.
     commit_on_enter: bool,
+    /// A Fence / WPolygon / CPolygon path being picked point by point. While
+    /// one is under way the host must send clicks here as points rather than
+    /// treating them as picks, which is what `is_selection_gathering` reports.
+    pick: Option<FencePick>,
+    /// Whether the polygon being picked takes what it merely touches. Ignored
+    /// by a fence, which has no inside to speak of.
+    pick_crossing: bool,
 }
 
 impl SelectObjectsCommand {
@@ -32,6 +40,8 @@ impl SelectObjectsCommand {
             pending_cmd: pending_cmd.to_string(),
             handles: Vec::new(),
             commit_on_enter: true,
+            pick: None,
+            pick_crossing: true,
         }
     }
 
@@ -42,6 +52,8 @@ impl SelectObjectsCommand {
             pending_cmd: pending_cmd.to_string(),
             handles: Vec::new(),
             commit_on_enter: false,
+            pick: None,
+            pick_crossing: true,
         }
     }
 }
@@ -52,6 +64,21 @@ impl CadCommand for SelectObjectsCommand {
     }
 
     fn prompt(&self) -> String {
+        if let Some(pick) = &self.pick {
+            let label = if !pick.closed {
+                t!("Fence")
+            } else if self.pick_crossing {
+                t!("Crossing polygon")
+            } else {
+                t!("Window polygon")
+            };
+            return t!(
+                "%{mode}: pick points (%{count} placed, Enter to apply):",
+                mode = label,
+                count = pick.len()
+            )
+            .into_owned();
+        }
         if self.commit_on_enter && !self.handles.is_empty() {
             t!(
                 "%{cmd}  Select objects (%{count} selected, Enter to apply):",
@@ -67,16 +94,30 @@ impl CadCommand for SelectObjectsCommand {
     // Opt into the selection-gathering path; host routes clicks through
     // the normal selection system and calls on_selection_complete after each action.
     fn is_selection_gathering(&self) -> bool {
-        true
+        // A path being picked needs the clicks as points; handing them to the
+        // selection system instead would pick objects under each vertex.
+        self.pick.is_none()
     }
 
-    // Clickable selection keywords (#426): Previous re-selects the set the
-    // last command worked on, Last the most recently created object. The
-    // keywords are consumed centrally in `try_selection_keyword`, so they
-    // also work typed — these buttons just surface them.
+    // Clickable selection keywords (#426, #596). Window and Crossing fix the
+    // sense of the next box, which dragging would otherwise take from the
+    // direction the corner travels; All takes the whole space; Add and Remove
+    // decide what a pick does for the rest of the selection; Previous
+    // re-selects the set the last command worked on, Last the most recently
+    // created object. All are consumed centrally in `try_selection_keyword`, so
+    // they work typed as well — these buttons only surface them, which is what
+    // the on-screen keyboard-less case needs.
     fn options(&self) -> Vec<CmdOption> {
         if self.commit_on_enter {
             vec![
+                CmdOption::new(t!("Window").as_ref(), "W"),
+                CmdOption::new(t!("Crossing").as_ref(), "C"),
+                CmdOption::new(t!("Fence").as_ref(), "F"),
+                CmdOption::new(t!("WPolygon").as_ref(), "WP"),
+                CmdOption::new(t!("CPolygon").as_ref(), "CP"),
+                CmdOption::new(t!("All").as_ref(), "ALL"),
+                CmdOption::new(t!("Add").as_ref(), "A"),
+                CmdOption::new(t!("Remove").as_ref(), "R"),
                 CmdOption::new(t!("Previous").as_ref(), "P"),
                 CmdOption::new(t!("Last").as_ref(), "L"),
             ]
@@ -99,13 +140,68 @@ impl CadCommand for SelectObjectsCommand {
         CmdResult::Relaunch(std::mem::take(&mut self.pending_cmd), handles)
     }
 
-    fn on_point(&mut self, _pt: DVec3) -> CmdResult {
+    fn on_point(&mut self, pt: DVec3) -> CmdResult {
+        if let Some(pick) = self.pick.as_mut() {
+            pick.push([pt.x, pt.y]);
+        }
         CmdResult::NeedPoint
     }
 
+    fn wants_text_input(&self) -> bool {
+        true
+    }
+
+    // Fence and the two polygons are picked here rather than centrally: they
+    // need somewhere to accumulate points, and the command is what outlives the
+    // individual clicks. The rest of the keywords act at once and are consumed
+    // in `try_selection_keyword`, which sees the token first. (#596)
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if !self.commit_on_enter {
+            return None;
+        }
+        match text.trim().to_uppercase().as_str() {
+            "F" | "FENCE" => {
+                self.pick = Some(FencePick::fence());
+                Some(CmdResult::NeedPoint)
+            }
+            "CP" | "CPOLYGON" => {
+                self.pick = Some(FencePick::polygon());
+                self.pick_crossing = true;
+                Some(CmdResult::NeedPoint)
+            }
+            "WP" | "WPOLYGON" => {
+                self.pick = Some(FencePick::polygon());
+                self.pick_crossing = false;
+                Some(CmdResult::NeedPoint)
+            }
+            _ => None,
+        }
+    }
+
+    fn on_preview_wires(&mut self, pt: DVec3) -> Vec<WireModel> {
+        match &self.pick {
+            Some(pick) if !pick.is_empty() => {
+                vec![pick.preview([pt.x, pt.y], "select_fence")]
+            }
+            _ => vec![],
+        }
+    }
+
     // Enter / right-click ends the gather phase and fires the pending command
     // with the accumulated selection. Nothing selected → cancel.
     fn on_enter(&mut self) -> CmdResult {
+        // Finishing a path applies it and returns to picking objects; the set
+        // it produced joins whatever was already gathered.
+        if let Some(pick) = self.pick.take() {
+            if pick.is_usable() {
+                return CmdResult::SelectByPath {
+                    path: pick.path(),
+                    closed: pick.closed,
+                    crossing: self.pick_crossing,
+                };
+            }
+            return CmdResult::NeedPoint;
+        }
         if !self.commit_on_enter || self.handles.is_empty() {
             return CmdResult::Cancel;
         }