step 4/4: the docs say permissions too, and capability means one thing again

44 files of prose — CLAUDE.md, AGENTS.md, TODO.md, 20 docs, both plugin design
documents, and the comment surface the earlier steps could not reach.

Applied against an explicit keep-list, not swept, because the word turned out to
have SIX meanings in this repository rather than the three the offscale doc
recorded:

  permissions          renamed (steps 1–2)
  $OFFICER_ROOT/capabilities/  KEPT — the item store, and now the only thing
                               the word means that is ours
  sidecar routing keys renamed to `handles` (step 3)
  Lightning wallet     KEPT — a domain term, and on the wire to the mobile apps
  terminfo queries     KEPT — XTGETTCAP, in the pty sidecar
  InvoiceShelf         KEPT — per-resource { write, bulkDelete } flags

The sweep still falsified two things, both caught by checking rather than by
review, and both in prose that discusses more than one meaning at once:

CLAUDE.md began claiming the item store lives at `$OFFICER_ROOT/permissions`.
It does not; that directory is on disk and full of skills and tools.

And the offscale doc's own note about the collision became
"Named `permissions`, NOT `permissions`" — a sentence that had eaten the thing
it existed to warn about.

Both restored, and the note rewritten to say what is now true: capability means
one thing of ours, and three that belong to somebody else's vocabulary.

Verified live after restart: self and admin permission endpoints 200, gated
route 200, agent-status 200, 9 grants intact with 6 permissions offered.
tsgo clean, 797 tests, 787 pass, same 7.

The rename is done. Four steps, no data lost, no client break that survived
the step it was introduced in.

plugins/music/web/MusicPlayerHost.tsx

@@ -123,7 +123,7 @@ export const MusicPlayerHost = () => {
   // Restore the saved "currently playing" on first load — paused, at its position — so a reload/return
   // lands back on the track. Skipped when a queue already exists (an in-app nav kept player state).
   //
-  // Also skipped without the `music` capability. This host is mounted by the shell for every account, so it
+  // Also skipped without the `music` permission. This host is mounted by the shell for every account, so it
   // used to reach for `/music/now-playing` on a member's very first paint and 403.
   useEffect(() => {
     if (restoredRef.current) return;