fix: widen undo dialog and polish its summary line

The undo/redo confirmation dialog capped at 60 columns and wrapped
even a short insert on wide terminals, showed a lowercase "snapshot
taken", a raw ISO-8601 timestamp, and lowercase yes/no labels.

Grow the dialog to fit its longest line (bounded 34–100), capitalise
Snapshot/Yes/No, and render the snapshot timestamp in local time,
human-formatted (24 May 2026, 11:00) via a new chrono dependency
(clock feature only; English month names). Yes/No capitalisation also
applies to the rebuild-confirm dialog.

Cargo.lock

@@ -23,6 +23,15 @@ version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"
 
+[[package]]
+name = "android_system_properties"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "819e7219dbd41043ac279b19830f2efc897156490d7fd6ea916720117ee66311"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "anyhow"
 version = "1.0.102"
@@ -155,6 +164,17 @@ dependencies = [
  "rand_core 0.10.1",
 ]
 
+[[package]]
+name = "chrono"
+version = "0.4.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c673075a2e0e5f4a1dde27ce9dee1ea4558c7ffe648f576438a20ca1d2acc4b0"
+dependencies = [
+ "iana-time-zone",
+ "num-traits",
+ "windows-link",
+]
+
 [[package]]
 name = "compact_str"
 version = "0.9.0"
@@ -189,6 +209,12 @@ dependencies = [
  "unicode-segmentation",
 ]
 
+[[package]]
+name = "core-foundation-sys"
+version = "0.8.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
+
 [[package]]
 name = "cpufeatures"
 version = "0.2.17"
@@ -675,6 +701,30 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
+[[package]]
+name = "iana-time-zone"
+version = "0.1.65"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e31bc9ad994ba00e440a8aa5c9ef0ec67d5cb5e5cb0cc7f8b744a35b389cc470"
+dependencies = [
+ "android_system_properties",
+ "core-foundation-sys",
+ "iana-time-zone-haiku",
+ "js-sys",
+ "log",
+ "wasm-bindgen",
+ "windows-core",
+]
+
+[[package]]
+name = "iana-time-zone-haiku"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f31827a206f56af32e590ba56d5d2d085f558508192593743f16b2306495269f"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "id-arena"
 version = "2.3.0"
@@ -1370,6 +1420,7 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "base64",
+ "chrono",
  "crossterm",
  "csv",
  "directories",

Cargo.toml

@@ -11,6 +11,10 @@ publish = false
 [dependencies]
 anyhow = "1.0.102"
 base64 = "0.22.1"
+# `clock` brings local-timezone support (UTC → machine local) for
+# the undo-dialog snapshot timestamp (issue #13). No locale feature:
+# month names stay English; `unstable-locales` is deliberately avoided.
+chrono = { version = "0.4.44", default-features = false, features = ["clock"] }
 crossterm = { version = "0.29.0", features = ["event-stream"] }
 csv = "1.4.0"
 directories = "6.0.0"

docs/requirements.md

@@ -453,7 +453,11 @@ handoff-14 cleanup; 449 after B2/C2.)
   undone / re-applied (`Y` confirms). *(Implemented 2026-05-24:
   `undo` / `redo` app commands, `Modal::UndoConfirm`, runtime
   prepare→confirm→restore→refresh; `--no-undo` reports undo is off,
-  empty stacks report "nothing to undo/redo".)*
+  empty stacks report "nothing to undo/redo". UX polish 2026-05-29,
+  issue #13: the confirm dialog grows to fit its summary on one row,
+  capitalises `Snapshot` / `Yes` / `No`, and renders the snapshot
+  timestamp in local time, human-formatted (`24 May 2026, 11:00`) via
+  the new `chrono` dependency.)*
 - [x] **U3** `history.log` records every submitted command in
   append-only form, tagged with its outcome (Iteration 2;
   broadened by ADR-0034). Format: `<ISO-8601 Z>|<status>|<source>`

src/friendly/strings/en-US.yaml

@@ -763,7 +763,7 @@ modal:
   redo_confirm_title: "Redo last undone change"
   undo_confirm_command: "This will undo:"
   redo_confirm_command: "This will re-apply:"
-  undo_confirm_when: "snapshot taken {timestamp}"
+  undo_confirm_when: "Snapshot taken {timestamp}"
   undo_confirm_prompt: "Restore that earlier state?"
   undo_cancelled: "undo cancelled"
   redo_cancelled: "redo cancelled"
@@ -807,8 +807,8 @@ shortcut:
   submit: "submit"
   confirm: "confirm"
   cancel: "cancel"
-  yes: "yes"
+  yes: "Yes"
-  no: "no"
+  no: "No"
   load: "load"
   select: "select"
   browse_path: "browse path"

src/snapshots/rdbms_playground__ui__tests__rebuild_confirm_modal_dark.snap

@@ -1,5 +1,6 @@
 ---
 source: src/ui.rs
+assertion_line: 1469
 expression: snapshot
 ---
 ╭ Tables ──────────────────╮╭ Output ──────────────────────────────────────────╮
@@ -16,7 +17,7 @@ expression: snapshot
 │         │                                                          │         │
 │         │Continue?                                                 │         │
 │         │                                                          │         │
-│         │[Y] yes   [N] no   Esc cancel                             │         │
+│         │[Y] Yes   [N] No   Esc cancel                             │         │
 │         ╰──────────────────────────────────────────────────────────╯─────────╯
 │                          │╭ SIMPLE ──────────────────────────────────────────╮
 │                          ││                                                  │

src/ui.rs

@@ -317,6 +317,52 @@ fn render_rebuild_confirm(summary: &str, theme: &Theme, frame: &mut Frame<'_>, a
     frame.render_widget(paragraph, dialog_area);
 }
 
+/// Format a stored ISO-8601 UTC timestamp for display in a
+/// confirmation dialog (issue #13): parse it, convert to the
+/// machine's local timezone, and render a fixed human-friendly
+/// form (`24 May 2026, 11:00`). Month names stay English — no
+/// locale feature. Falls back to the raw input if it can't be
+/// parsed; this is defensive only, since stored values are always
+/// `utc_iso8601_now()` output.
+fn format_snapshot_timestamp(iso: &str) -> String {
+    chrono::DateTime::parse_from_rfc3339(iso)
+        .map(|dt| format_local_datetime(dt.with_timezone(&chrono::Local)))
+        .unwrap_or_else(|_| iso.to_string())
+}
+
+/// Render a timezone-aware datetime in the fixed display form.
+/// Split out from [`format_snapshot_timestamp`] so the format can
+/// be unit-tested deterministically with a fixed offset (the
+/// `Local` conversion itself is machine-dependent).
+fn format_local_datetime<Tz>(dt: chrono::DateTime<Tz>) -> String
+where
+    Tz: chrono::TimeZone,
+    Tz::Offset: std::fmt::Display,
+{
+    dt.format("%-d %b %Y, %H:%M").to_string()
+}
+
+/// Preferred outer width (columns) for the undo/redo confirm
+/// dialog (issue #13): wide enough to hold the longest content
+/// line on a single row, clamped to sane bounds and the available
+/// area so a short insert no longer wraps on roomy terminals.
+fn undo_dialog_width(
+    content_widths: impl IntoIterator<Item = usize>,
+    area_width: u16,
+) -> u16 {
+    /// Floor — comfortably fits the button row plus borders.
+    const MIN: u16 = 34;
+    /// Ceiling for outlier (ultra-wide) terminals.
+    const MAX: u16 = 100;
+    let widest = content_widths.into_iter().max().unwrap_or(0);
+    // +4: left/right border (2) + one padding column each side (2).
+    let preferred =
+        u16::try_from(widest).unwrap_or(u16::MAX).saturating_add(4);
+    let upper = area_width.min(MAX);
+    let lower = MIN.min(upper);
+    preferred.clamp(lower, upper)
+}
+
 /// `undo` / `redo` confirmation modal (ADR-0006 Amendment 1). Names
 /// the command that will be undone / re-applied and when its
 /// snapshot was taken, then prompts `Y` / `N`.
@@ -326,19 +372,48 @@ fn render_undo_confirm(
     frame: &mut Frame<'_>,
     area: Rect,
 ) {
-    let dialog_w = area.width.clamp(20, 60);
-    let inner_w = dialog_w.saturating_sub(4) as usize;
-
     let intro = if m.is_redo {
         crate::t!("modal.redo_confirm_command")
     } else {
         crate::t!("modal.undo_confirm_command")
     };
-    let mut body_lines: Vec<String> = wrap_lines(&format!("{intro} {}", m.command), inner_w);
+    let title = if m.is_redo {
-    body_lines.extend(wrap_lines(
+        crate::t!("modal.redo_confirm_title")
-        &crate::t!("modal.undo_confirm_when", timestamp = m.timestamp),
+    } else {
-        inner_w,
+        crate::t!("modal.undo_confirm_title")
-    ));
+    };
+    let intro_line = format!("{intro} {}", m.command);
+    // Local-time, human-formatted snapshot stamp (issue #13).
+    let when_display = format_snapshot_timestamp(&m.timestamp);
+    let when_line =
+        crate::t!("modal.undo_confirm_when", timestamp = when_display);
+    let prompt = crate::t!("modal.undo_confirm_prompt");
+    // Reconstruct the button row purely to measure its width — the
+    // styled spans are built below. Keep this in sync with them.
+    let buttons_measure = format!(
+        "[Y] {}   [N] {}   Esc {}",
+        crate::t!("shortcut.yes"),
+        crate::t!("shortcut.no"),
+        crate::t!("shortcut.cancel"),
+    );
+
+    // Grow the dialog to fit the longest content line on one row
+    // (issue #13). The title sits in the border, so it needs two
+    // extra columns for the surrounding spaces.
+    let dialog_w = undo_dialog_width(
+        [
+            title.chars().count() + 2,
+            intro_line.chars().count(),
+            when_line.chars().count(),
+            prompt.chars().count(),
+            buttons_measure.chars().count(),
+        ],
+        area.width,
+    );
+    let inner_w = dialog_w.saturating_sub(4) as usize;
+
+    let mut body_lines: Vec<String> = wrap_lines(&intro_line, inner_w);
+    body_lines.extend(wrap_lines(&when_line, inner_w));
     let body_height = body_lines.len() as u16;
     // Title row + blank + body + blank + prompt + blank + keys + borders (2).
     let dialog_h = body_height.saturating_add(7).min(area.height);
@@ -354,11 +429,6 @@ fn render_undo_confirm(
 
     frame.render_widget(ratatui::widgets::Clear, dialog_area);
 
-    let title = if m.is_redo {
-        crate::t!("modal.redo_confirm_title")
-    } else {
-        crate::t!("modal.undo_confirm_title")
-    };
     let title_style = Style::default().fg(theme.fg).add_modifier(Modifier::BOLD);
     let block = Block::default()
         .borders(Borders::ALL)
@@ -376,7 +446,7 @@ fn render_undo_confirm(
         text_lines.push(Line::from(line));
     }
     text_lines.push(Line::from(""));
-    text_lines.push(Line::from(crate::t!("modal.undo_confirm_prompt")));
+    text_lines.push(Line::from(prompt));
     text_lines.push(Line::from(""));
     text_lines.push(Line::from(vec![
         Span::styled("[Y]", Style::default().fg(theme.fg).add_modifier(Modifier::BOLD)),
@@ -1399,6 +1469,92 @@ mod tests {
         insta::assert_snapshot!("rebuild_confirm_modal_dark", snapshot);
     }
 
+    // ---- Issue #13: undo confirm dialog -------------------------
+
+    #[test]
+    fn format_local_datetime_renders_fixed_human_form() {
+        // Deterministic: a fixed offset (not Local) so the output
+        // does not depend on the test machine's timezone.
+        let dt = chrono::DateTime::parse_from_rfc3339("2026-05-24T11:05:00+02:00")
+            .expect("valid rfc3339");
+        assert_eq!(format_local_datetime(dt), "24 May 2026, 11:05");
+        // Single-digit day: no leading zero on the day, but zero-
+        // padded hour.
+        let dt = chrono::DateTime::parse_from_rfc3339("2026-05-04T09:05:00+00:00")
+            .expect("valid rfc3339");
+        assert_eq!(format_local_datetime(dt), "4 May 2026, 09:05");
+    }
+
+    #[test]
+    fn format_snapshot_timestamp_drops_machine_syntax() {
+        // The stored UTC string is reformatted: no 'T'/'Z' machine
+        // syntax survives, and the year is preserved. (Day/month
+        // can shift across the date line depending on local TZ, so
+        // we assert only the stable parts.)
+        let out = format_snapshot_timestamp("2026-07-24T10:00:00Z");
+        assert!(!out.contains('T'), "no date/time 'T' separator: {out}");
+        assert!(!out.contains('Z'), "no UTC 'Z' suffix: {out}");
+        assert!(out.contains("2026"), "year preserved: {out}");
+    }
+
+    #[test]
+    fn format_snapshot_timestamp_falls_back_on_garbage() {
+        assert_eq!(format_snapshot_timestamp("not a timestamp"), "not a timestamp");
+    }
+
+    #[test]
+    fn undo_dialog_width_grows_to_fit_and_clamps() {
+        // Grows to the widest line + 4 (borders + padding).
+        assert_eq!(undo_dialog_width([50usize], 120), 54);
+        // Floors at MIN (34) for tiny content.
+        assert_eq!(undo_dialog_width([3usize], 120), 34);
+        // Caps at MAX (100) for absurdly long content.
+        assert_eq!(undo_dialog_width([400usize], 120), 100);
+        // Never exceeds the available area, and never panics when
+        // the area is narrower than MIN.
+        assert_eq!(undo_dialog_width([50usize], 40), 40);
+        assert_eq!(undo_dialog_width([50usize], 10), 10);
+    }
+
+    #[test]
+    fn undo_modal_command_does_not_wrap_on_wide_terminal() {
+        use crate::app::{Modal, UndoConfirmModal};
+        let mut app = App::new();
+        app.modal = Some(Modal::UndoConfirm(UndoConfirmModal {
+            command: "insert into Customers values (1, 'Oliver Sturm')".to_string(),
+            timestamp: "2026-05-24T10:00:00Z".to_string(),
+            is_redo: false,
+        }));
+        let theme = Theme::dark();
+        let out = render_to_string(&mut app, &theme, 120, 30);
+        assert!(
+            out.lines().any(|l| l.contains(
+                "This will undo: insert into Customers values (1, 'Oliver Sturm')"
+            )),
+            "command must sit on one row on a wide terminal:\n{out}"
+        );
+    }
+
+    #[test]
+    fn undo_modal_uses_capitalized_labels_and_formatted_time() {
+        use crate::app::{Modal, UndoConfirmModal};
+        let mut app = App::new();
+        app.modal = Some(Modal::UndoConfirm(UndoConfirmModal {
+            command: "delete from T where id = 1".to_string(),
+            timestamp: "2026-05-24T10:00:00Z".to_string(),
+            is_redo: false,
+        }));
+        let theme = Theme::dark();
+        let out = render_to_string(&mut app, &theme, 120, 30);
+        assert!(out.contains("Snapshot taken"), "capitalized Snapshot:\n{out}");
+        assert!(out.contains("[Y] Yes"), "capitalized Yes:\n{out}");
+        assert!(out.contains("[N] No"), "capitalized No:\n{out}");
+        assert!(
+            !out.contains("2026-05-24T10:00:00Z"),
+            "raw ISO timestamp must not appear:\n{out}"
+        );
+    }
+
     #[test]
     fn populated_with_table_snapshot() {
         // Items panel lists tables; output panel shows the