feat(commands): add CLOSE, HIDE, VISUALSTYLES, QUICKCALC, HYPERLINK, XOPEN

Six more standard commands by reusing existing infrastructure:
- CLOSE: close the active tab (Message::TabClose)
- HIDE / VISUALSTYLES: per-viewport render mode (Message::SetRenderMode)
- QUICKCALC / QC: alias the CAL arithmetic evaluator
- HYPERLINK <url>: attach a hyperlink via the PE_URL XData record
- XOPEN: open a selected xref's source file (Message::OpenRecent)

COMMANDS.md updated to 214 done / 15 partial / 33 missing of 262.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/commands/inquiry.rs

@@ -45,10 +45,16 @@ impl OpenCADStudio {
                 return Some(Task::done(Message::QSelectOpen));
             }
 
-            // CAL <expression> — evaluate an arithmetic expression
+            // CAL / QUICKCALC <expression> — evaluate an arithmetic expression
             //   (+ - * /, parentheses, unary minus, decimals).
-            cmd if cmd == "CAL" || cmd.starts_with("CAL ") => {
-                let expr = cmd.trim_start_matches("CAL").trim();
+            cmd if cmd == "CAL"
+                || cmd == "QUICKCALC"
+                || cmd == "QC"
+                || cmd.starts_with("CAL ")
+                || cmd.starts_with("QUICKCALC ")
+                || cmd.starts_with("QC ") =>
+            {
+                let expr = cmd.splitn(2, char::is_whitespace).nth(1).unwrap_or("").trim();
                 if expr.is_empty() {
                     self.command_line
                         .push_info("Usage: CAL <expression>   e.g. CAL (2+3)*4");