Set the chart's placeholder version to 0.28.1

Cosmetic: make helm-package sets the published version and appVersion
from the tag, so these two fields decide nothing (see the comment
above them). Kept in step anyway, same as 36c00ac and 9bf4c92, so a
tree heading for v0.28.1 doesn't say 0.28.0.

charts/terdut-server/Chart.yaml

@@ -15,5 +15,5 @@ type: application
 # appVersion and image.tag in values.yaml no longer agree, and that is not an oversight:
 # image.tag stays "latest", which is what a local install actually pulls. appVersion is
 # metadata and drives nothing.
-version: 0.28.0
+version: 0.28.1
-appVersion: "v0.28.0"
+appVersion: "v0.28.1"

internal/web/static/js/format.js

@@ -82,15 +82,6 @@ export function addDays(d, n) {
   return r;
 }
 
-// ISO 8601 week number.
-export function isoWeek(d) {
-  const t = new Date(Date.UTC(d.getFullYear(), d.getMonth(), d.getDate()));
-  const day = t.getUTCDay() || 7;
-  t.setUTCDate(t.getUTCDate() + 4 - day);
-  const yearStart = new Date(Date.UTC(t.getUTCFullYear(), 0, 1));
-  return Math.ceil(((t - yearStart) / DAY + 1) / 7);
-}
-
 export const STATUS_LABEL = {
   triggered: 'Triggered',
   acknowledged: 'Acknowledged',