DNSWATCHER_SENTRY_DSN was read but never used. This ports the Sentry
integration from gohttpserver with sentry-go v0.49.0. The server's start
hook calls sentry.Init when the DSN is set; a DSN Sentry cannot parse
fails the hook, so startup stops with the parse error. sentryhttp, with
Repanic, reports handler panics and passes them on to chi's Recoverer.
Shutdown sends queued reports once the HTTP server has stopped. The
client uses the older transport (DisableTelemetryBuffer): with the
default one, Flush can return before sending a report made just before
it. Client reports are off, so only panics are sent. The DSN is checked
at server start, not in config, so the config test is unchanged.
sentry-go raises several golang.org/x modules and moves go-spew and
go-difflib to untagged commits.
Model: opus-5-5
sneak