v0.13.2

Detect-and-guide for the age CLI dependency.

Added

• envpkt doctor — one-shot environment check: is the age CLI installed, is a config
  resolvable for this directory, and do its sealed secrets decrypt with an available key? Reuses
  the boot resolution path, so a missing key reports the same searched-paths guidance as a failed
  boot. Exits non-zero if a check fails.

Changed

• Clearer guidance when the age CLI is missing. AgeNotFound errors (from keygen, seal,
  decryption) now print a platform-aware install command (brew install age / apt install age /
  scoop install age) plus the install link, instead of a bare "not found" message.

Full Changelog: v0.13.1...v0.13.2