Log timestamp normalizer

Timezone rules come from this browser's built-in IANA database; nothing is uploaded, logged or stored. Values without an offset are read in the source zone you picked, never this device's local time. The sniffer covers ISO 8601, Apache CLF, BSD syslog, RFC 2822, Windows FILETIME, /Date()/, epoch seconds through nanoseconds, and numeric dates; it does not read RFC 5424's high-precision syslog form, named RFC 2822 zones like EST, or leap seconds. Every assumption is flagged on its row instead of being resolved silently: an assumed source zone, a DST overlap settled to the earlier instant, a DST gap settled to the offset in force before the change, a day-month ambiguity, a syslog year you supplied, and dropped sub-millisecond digits.