v0.5.1

Fixed

• The Updater tells a program from a plugin. opencode-worktree@latest in a plugin list names a
  command-line tool on npm, with no plugin entry points; OpenCode refuses it, and the Updater used to
  propose pinning it and then fail with that same refusal. It now reads the installed manifest and
  applies OpenCode's own rule — exports["./tui"], exports["./server"], main or oc-themes —
  and lists anything else as not a plugin, with the file to remove the entry from. What OpenCode
  already loaded is never questioned, and a manifest it cannot read proves nothing.
• A pin says what it is for. The review showed 0.4.1 → 0.4.1, which read as a bug; it now reads
  0.4.1 · pin, so latest cannot freeze again.
• A watch sees what the run printed before it was attached. A shell that failed in its first
  milliseconds could print its failure before shell.watch arrived, and the run was judged without
  it. A new watcher is now caught up on the current run's recent output — never an earlier run's —
  and on its exit, if it has already ended.