L-10: E-16 answers not_found for another user's device (D-156)

A member naming the other user's device now gets the same 404 not_found
body as an unknown id, so E-16 no longer reveals whose a device id is.
The admin keeps revoking any device except the current one (AC-3.2, §8.4).
contracts/openapi.yaml drops the 403 on E-16 and states the rule;
web/src/api/schema.d.ts regenerated. The forbidden test becomes a
not_found test, plus one asserting the body equals the unknown-id body
and that nothing was revoked.

Also bumps ctutils 0.4.3 -> 0.4.4 (lockfile only) for RUSTSEC-2026-0385,
published 2026-10-23, which failed cargo audit on main.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TQd3pEP9UeN2uifbHknQ7B

contracts/openapi.yaml

@@ -626,7 +626,7 @@ paths:
     delete:
       operationId: revokeDevice
       summary: E-16 Revoke a device
-      description: Revoking an already revoked device is 204. Admin any device except the current one; member own devices except the current one (SPEC §8.4).
+      description: Revoking an already revoked device is 204. Admin any device except the current one; member own devices except the current one, and a device of the other user is 404 `not_found`, the same answer as an unknown id (SPEC §8.4, D-156).
       parameters:
         - $ref: '#/components/parameters/DeviceId'
         - $ref: '#/components/parameters/Protocol'
@@ -641,9 +641,6 @@ paths:
               $ref: '#/components/headers/ServerVersion'
         '401':
           $ref: '#/components/responses/Unauthorized'
-        '403':
-          $ref: '#/components/responses/Forbidden'
-          description: '`forbidden`.'
         '404':
           $ref: '#/components/responses/NotFound'
           description: '`not_found`.'