v0.40.0

Plugin updates now reach you: one command updates every plugin on the machine, shows which open
sessions are still on an old build, tells a session when a plugin it loaded was updated, and removes
old builds nobody uses.

Added

• /board plugins updates every installed plugin in one pass (#712). It refreshes each marketplace,
  updates each plugin, and reports old -> new version and commit with a short "what's new". A failed
  refresh or update is reported as failed (and the exit code is non-zero), never as "up to date".
• /board plugins sessions lists open sessions that are still on an old build (#713). For each it
  says whether /reload-plugins is enough or the plugin ships an MCP server and needs a new session.
  A session with no usage record reads as unknown, never as up to date; sessions that are not live are
  never listed (liveness by process id and start time, so a recycled id is not mistaken for a session).
• A running session is told once when a plugin it loaded was updated (#714). A UserPromptSubmit
  hook shows one plain-language notice per session, plugin and new build. A cmd shim in front of it
  (the same approach as the brake's, #572) keeps a steady-state prompt at about 0.15-0.35 s instead of
  about 2 s: it skips starting PowerShell while the installed list is unchanged since that session's
  last conclusive check. Only sessions started with a build that contains the hook can show the notice;
  the session map covers the rest.
• /board plugins clean removes old cached builds nobody uses (#715). It lists by default and
  deletes only with -Execute. A build is removed only when it is not installed, no live process holds
  it, it is a real folder strictly inside the plugin cache (no links), and it was not touched recently;
  each build is re-checked right before its own deletion, and any doubt keeps it.

Changed

• .cmd files are checked out with CRLF line endings (.gitattributes), because cmd.exe can
  misparse labels in LF-only files; this also covers the brake's shim.