Drops the hardcoded German strings ("Briefverteilung in diesem Zeitraum",
"{n} von {name}") and routes every visible + assistive-tech string
through dist_bar_aria and dist_bar_segment message keys. An English
or Spanish user now sees "from" / "de" instead of "von" both on
screen and in the aria-label their screen reader announces.
Refs #305
Fixes @leonievoss i18n concern from PR review
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
858c9f0564