viewer: click to copy values, amounts, and identifiers

Company details (EIN, state number, address, every profile value), an
entry's number and amount, an account's code and balance, a document's
file name and SHA-256 copy on click: a pointer and copy icon on hover,
a check for a moment after. Amounts copy as their exact plain decimal
(fmt::plain: no "$", commas, or parentheses; "-" for negatives); where a
click already drills down (report cells, register and transaction rows,
general ledger lines), a right-click menu copies the amounts, the entry
number, or the description. The sidebar's chain check copies the
journal head and data folder.

tests/copy.rs: every display style copies back to the exact value
(property), and clicking the EIN, an entry's amount, and its number puts
exactly that on the clipboard.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GWVo7x3UHw5kwCUaWxiejX

crates/ledger-gui/src/pages/entry.rs

@@ -24,10 +24,12 @@ pub fn detail(ui: &mut Ui, b: &Books, e: &EntryInfo, shell: &mut Shell<'_>) {
         .auto_shrink(false)
         .show(ui, |ui| {
             ui.horizontal(|ui| {
-                ui.label(
+                widgets::copyable(
+                    ui,
                     RichText::new(format!("Entry #{}", e.id))
                         .font(theme::regular(12.5))
                         .color(p.muted),
+                    &format!("#{}", e.id),
                 );
                 ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
                     if ui
@@ -106,7 +108,11 @@ pub fn detail(ui: &mut Ui, b: &Books, e: &EntryInfo, shell: &mut Shell<'_>) {
                     ui.label(fmt::date(e.date));
                     ui.end_row();
                     k(ui, "Amount");
-                    ui.label(RichText::new(fmt::dollars(e.amount)).font(theme::semibold(14.0)));
+                    widgets::copyable(
+                        ui,
+                        RichText::new(fmt::dollars(e.amount)).font(theme::semibold(14.0)),
+                        &fmt::plain(&fmt::dollars(e.amount)).unwrap_or_default(),
+                    );
                     ui.end_row();
                     if let Some(c) = &created {
                         k(ui, "Recorded");