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.

docs/mobile-dav-provisioning.md

@@ -60,7 +60,7 @@ speaks DAV.
 
 - **Username** = the account's email address — the signed-in account's own, not a constant. (This said
   "Officer is single-user; there is exactly one" until 2026-08-07. `calendar` is now a grantable
-  capability, so a member can hold their own app passwords and their own collections.)
+  permission, so a member can hold their own app passwords and their own collections.)
 - **Password** = a **DAV app password**, not the login password.
 
 DAV app passwords are argon2-hashed at rest, scoped to `/dav` and nothing else, and **the plaintext is
@@ -106,7 +106,7 @@ row, the sidecar forwards it to Radicale as `X-Remote-User`, and Radicale's stor
 
 **Do not hardcode `1`.** This passage used to say that on a single-user instance — "which every Officer
 instance is" — the value is always `1`. That stopped being true on 2026-08-07: members can hold the
-`calendar` capability, and a member's id is not 1. Derive it from `/auth/me` or from the collection
+`calendar` permission, and a member's id is not 1. Derive it from `/auth/me` or from the collection
 paths; both work, and both stay correct when the caller is not the owner.
 
 **A collection cannot live outside `/dav/<userId>/`.** Two independent guards: the sidecar rejects any