pm 0.15.4

An agent starting work now sees the design pages of its area: pm sprint open and a session's first pm task claim in a sprint list them.

Upgrade guide

1. On each machine, install the release: curl -fsSL https://github.com/Yeeef/pm/releases/download/pm-v0.15.4/install.sh | sh.
2. In the repo, run pm upgrade --to 0.15.4, then commit what it changes and merge it, as an ordinary PR.

Added

• pm sprint open prints the design pages its project's record lists, one line each: slug, title and link.
• pm task claim prints, on the session's first claim in the task's sprint, the design pages the sprint's record and then the project's list, without repeats; a task directly under a project gets the project's. A slug that names no design page shows as missing. prime.md says to read the pages the task touches before changing their code.