Feat: DIST / ID / AREA inquiry commands

Add three classic CAD measurement commands:
- DIST (DI): two-point pick → distance, angle, delta XYZ
- ID: one-point pick → coordinates
- AREA: multi-point polygon pick (Enter to close) → area + perimeter

New CmdResult::Measurement(String) variant ends active command and
prints result to command line without modifying the document.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/cmd_result.rs

@@ -364,6 +364,13 @@ impl H7CAD {
                 self.tabs[i].scene.zoom_to_window(p1, p2);
                 self.command_line.push_output("Zoom Window");
             }
+            CmdResult::Measurement(msg) => {
+                self.tabs[i].active_cmd = None;
+                self.tabs[i].snap_result = None;
+                self.tabs[i].scene.clear_preview_wire();
+                self.restore_pre_cmd_tangent();
+                self.command_line.push_output(&msg);
+            }
         }
         // Focus the command-line input while a command is active; blur it when the command ends.
         if self.tabs[i].active_cmd.is_some() {

src/app/commands.rs

@@ -970,6 +970,28 @@ impl H7CAD {
                 }
             }
 
+            // ── Inquiry ──────────────────────────────────────────────────────
+            "DIST"|"DI" => {
+                use crate::modules::home::inquiry::dist::DistCommand;
+                let cmd = DistCommand::new();
+                self.command_line.push_info(&cmd.prompt());
+                self.tabs[i].active_cmd = Some(Box::new(cmd));
+            }
+
+            "ID" => {
+                use crate::modules::home::inquiry::id::IdCommand;
+                let cmd = IdCommand::new();
+                self.command_line.push_info(&cmd.prompt());
+                self.tabs[i].active_cmd = Some(Box::new(cmd));
+            }
+
+            "AREA" => {
+                use crate::modules::home::inquiry::area::AreaCommand;
+                let cmd = AreaCommand::new();
+                self.command_line.push_info(&cmd.prompt());
+                self.tabs[i].active_cmd = Some(Box::new(cmd));
+            }
+
             "HELP"|"?" => {
                 self.command_line.push_output(
                     "Draw: LINE CIRCLE ARC PLINE RECT POLY POINT ELLIPSE SPLINE RAY XLINE HATCH  |  \
@@ -977,6 +999,7 @@ impl H7CAD {
                      Array: ARRAY ARRAYRECT ARRAYPOLAR ARRAYPATH  |  \
                      Text: TEXT MTEXT LEADER MLEADER  |  \
                      Dimension: DIMLINEAR DIMANGULAR DIMRADIUS  |  \
+                     Inquiry: DIST ID AREA LIST  |  \
                      View: ZOOM EXTENTS VIEW LIST/SAVE/RESTORE/DELETE  |  \
                      Layer: LAYER LIST/NEW/ON/OFF/FREEZE/THAW/LOCK/UNLOCK/COLOR/SET  |  \
                      Viewport: MVIEW VPLAYER VPORTS MS PS DRAWORDER  |  \