3.9.5

This patch improves Worker client and lease-grant handling while preserving the 3.9 series support contract.

• Reuse the activity helper client across tasks, with conservative charging of the original poll round trip before reusing a grant. Delayed, short or unknown grants still require confirmation before a callback.
• Avoid redundant workflow-lease renewal when a supported Server supplies a fresh clock-bound grant. Older Servers retain the heartbeat fallback.
• Update the optional Laravel example's locked Symfony patch dependencies.

Includes #326 and #327, plus the delayed-grant regression fix from #338/#339. PHP 8.1–8.4, framework, static-analysis, corpus and package checks passed. Published-package and installed behavior verification is recorded in #337; no benchmark or new Server capability is claimed by this release.