Timezone filter

Times that are always right, for everyone. The Timezone filter rewrites date/times inserted with its companion editor plugin (tiny_timezone) into each viewer's own timezone: a teacher in London writes "the webinar starts at 14:00" and a student in Sydney reads it as 23:00 local time, automatically. The original timestamp and source timezone travel inside the page markup, so the conversion is exact across daylight-saving boundaries and safe to repeat. If the filter is ever disabled, readers still see the full original date with its timezone — nothing breaks. The display format is configurable site-wide.