Count the other progress bar too

Double-tapping the year bar asks for a birth year and a life expectancy,
and a second bar appears below measuring one against the other. Tab moves
between the two, Enter commits the pair, Escape drops them. Hovering the
bar names the thing, and double-tapping it puts it away again.

A birth year rather than an age, so the bar keeps counting on its own
instead of going stale the moment it is entered. Expectancy defaults to
ninety and falls back to it when what is entered makes no sense, so the
bar always has something to measure against; a birth year that makes no
sense leaves the bar hidden instead, which is also where it starts.
Putting the bar away keeps the expectancy, so setting a birth year again
brings your own number back rather than the default.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

shell/plugins/panels/clock/Model.js

@@ -149,6 +149,63 @@ function yearProgressPercent(year, month, day) {
   return Math.round(yearProgress(year, month, day) * 100)
 }
 
+// Memento mori. The default span is a round number rather than anything from
+// an actuarial table: the point of the bar is the reminder, not the
+// arithmetic, and whoever wants a different number can say so.
+var DEFAULT_LIFE_EXPECTANCY = 90
+
+// A birth year rather than an age, so the bar keeps counting on its own
+// instead of going stale the moment it is entered. 0 means "not set", which
+// is also what a blank, malformed, future, or implausibly distant year means.
+function parseBirthYear(value, currentYear) {
+  var now = Math.round(Number(currentYear))
+  if (!isFinite(now)) return 0
+  var text = String(value === undefined || value === null ? "" : value).replace(/^\s+|\s+$/g, "")
+  if (!/^\d{4}$/.test(text)) return 0
+  var year = parseInt(text, 10)
+  if (!isFinite(year) || year > now || year < now - 120) return 0
+  return year
+}
+
+// Whole years, the way people say their age: born in 1979 makes you 47 for
+// all of 2026, whichever side of your birthday today falls.
+function ageFromBirthYear(birthYear, currentYear) {
+  var born = parseBirthYear(birthYear, currentYear)
+  if (born <= 0) return 0
+  return Math.round(Number(currentYear)) - born
+}
+
+// 0 means "not set", which is also what a blank, negative, fractional, or
+// absurd entry means — the life bar simply stays hidden.
+function parseAge(value) {
+  var text = String(value === undefined || value === null ? "" : value).replace(/^\s+|\s+$/g, "")
+  if (!/^\d+$/.test(text)) return 0
+  var years = parseInt(text, 10)
+  if (!isFinite(years) || years <= 0 || years > 120) return 0
+  return years
+}
+
+// Unset or nonsense falls back to the default rather than to zero, so the
+// bar always has something to measure against.
+function parseLifeExpectancy(value) {
+  var text = String(value === undefined || value === null ? "" : value).replace(/^\s+|\s+$/g, "")
+  if (!/^\d+$/.test(text)) return DEFAULT_LIFE_EXPECTANCY
+  var years = parseInt(text, 10)
+  if (!isFinite(years) || years <= 0 || years > 150) return DEFAULT_LIFE_EXPECTANCY
+  return years
+}
+
+function lifeProgress(age, expectancy) {
+  var years = parseAge(age)
+  var span = parseLifeExpectancy(expectancy)
+  if (years <= 0 || span <= 0) return 0
+  return Math.max(0, Math.min(1, years / span))
+}
+
+function lifeProgressPercent(age, expectancy) {
+  return Math.round(lifeProgress(age, expectancy) * 100)
+}
+
 // Always six rows of seven days. A fixed grid keeps the popup exactly the
 // same height in every month, so stepping through the year never makes the
 // panel jump under the pointer.
@@ -212,6 +269,12 @@ if (typeof module !== "undefined") {
     daysInYear: daysInYear,
     yearProgress: yearProgress,
     yearProgressPercent: yearProgressPercent,
+    parseAge: parseAge,
+    parseBirthYear: parseBirthYear,
+    ageFromBirthYear: ageFromBirthYear,
+    parseLifeExpectancy: parseLifeExpectancy,
+    lifeProgress: lifeProgress,
+    lifeProgressPercent: lifeProgressPercent,
     monthGrid: monthGrid,
     stepMonth: stepMonth,
     clockFormats: clockFormats,