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/mod.rs

@@ -333,6 +333,15 @@ inventory::submit!(crate::command::CommandRegistration {
         // Copy nested objects out of a block.
         "NCOPY",
         "NCOPYALL",
+        // Close tab, hidden-line / visual styles, calculator, hyperlink.
+        "CLOSE",
+        "HIDE",
+        "HI",
+        "VISUALSTYLES",
+        "QUICKCALC",
+        "QC",
+        "HYPERLINK",
+        "XOPEN",
         // Slice/section + interference + press-pull/thicken + 3D transforms + wall/pyramid.
         "SLICE",
         "SL",