Feat: ALIGN command (AL) — align objects using 1 or 2 point pairs

Workflow: select objects → 1st src/dst pair → 2nd src/dst pair (optional) → Enter.
- 1 pair: pure translation (src1 → dst1)
- 2 pairs: translate + rotate in XZ plane; optional uniform scale (Y/N prompt)

Transform applied as 3 sequential scene.transform_entities calls:
translate to origin → scale → rotate → translate to dst1.

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

src/app/commands.rs

@@ -985,6 +985,13 @@ impl H7CAD {
                 self.tabs[i].active_cmd = Some(Box::new(cmd));
             }
 
+            "ALIGN"|"AL" => {
+                use crate::modules::home::modify::align::AlignCommand;
+                let cmd = AlignCommand::new();
+                self.command_line.push_info(&cmd.prompt());
+                self.tabs[i].active_cmd = Some(Box::new(cmd));
+            }
+
             "LENGTHEN"|"LEN" => {
                 use crate::modules::home::modify::lengthen::LengthenCommand;
                 let cmd = LengthenCommand::new();
@@ -1031,7 +1038,7 @@ impl H7CAD {
             "HELP"|"?" => {
                 self.command_line.push_output(
                     "Draw: LINE CIRCLE ARC PLINE RECT POLY POINT ELLIPSE SPLINE RAY XLINE HATCH  |  \
-                     Modify: MOVE COPY ROTATE SCALE MIRROR ERASE OFFSET EXTEND FILLET CHAMFER STRETCH EXPLODE TRIM BREAK JOIN LENGTHEN  |  \
+                     Modify: MOVE COPY ROTATE SCALE MIRROR ERASE OFFSET EXTEND FILLET CHAMFER STRETCH EXPLODE TRIM BREAK JOIN LENGTHEN ALIGN  |  \
                      Array: ARRAY ARRAYRECT ARRAYPOLAR ARRAYPATH  |  \
                      Text: TEXT MTEXT LEADER MLEADER  |  \
                      Dimension: DIMLINEAR DIMANGULAR DIMRADIUS  |  \