Rename Copy to Send and put it first in the row context menu

The main feature (copy selection to the other panel, F5) is now labeled
"Send" in the toolbar button, tooltips, and context menu across all 7
locales. Internal identifiers (copyToOtherPanel, ctx-copy, i18n keys)
and secondary strings (toasts, status bar, errors) are unchanged.
The context-menu entry moves ahead of Open/Edit as the first row item.
README, marketing site, and the Windows QA checklist updated to match.

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

src/shared/i18n/en.ts

@@ -82,9 +82,9 @@ export const en = {
 	},
 	panel: {
 		choosePanel: "Choose what this panel shows",
-		copy: "Copy",
-		copyToRight: "Copy to right panel (F5)",
-		copyToLeft: "Copy to left panel (F5)",
+		copy: "Send",
+		copyToRight: "Send to right panel (F5)",
+		copyToLeft: "Send to left panel (F5)",
 		edit: "Edit",
 		editFile: "Edit file (F4)",
 		rename: "Rename (F2)",
@@ -286,7 +286,7 @@ export const en = {
 		open: "Open",
 		openDefault: "Open with the default application",
 		edit: "Edit",
-		copyToOther: "Copy to Other Panel",
+		copyToOther: "Send to Other Panel",
 		rename: "Rename",
 		permissions: "Permissions",
 		copyPath: "Copy Path",