- RequestContext::__isset()/__unset() — truthful isset() on unset-and-proxied
  superglobal slots (coroutine-legacy populate, #346 Apache bridge). Closes the
  ext-zealphp#42 residual: $g->server['X'] ?? fallback no longer silently takes
  the fallback, and app-side defensive guards (if (!isset($g->server))
  $g->server = [];) can no longer wipe the live $_SERVER through __set.
  Root-caused + verified live on the labs parity rig — full original #42 route
  table green, LEGACY byte-equivalent to COROUTINE mode.
- __unset stays a no-op for proxied names so framework slot-detach can never
  escalate into superglobal deletion (a re-bridge nuked $_ENV pre-guard).
- CHANGELOG hygiene: stray [Unreleased] entries re-homed (locale/umask -> 0.4.6,
  TableSessionHandler -> 0.4.5), preamble deduped.