chore: drop server-internal terminology from public-facing artifacts

Public docstrings, comments, and test method names previously leaked
server-side implementation hints (the V3 form / model-level / form-
level distinction, V35 short-form tag) that exposed engine details
beyond the API contract. Rephrase them to describe externally
observable server behaviour only — 'the server returns 422 for ...'
in place of 'the server's V3 form rejects (model-level/form-level)' —
and rename the V35 test method to a name that describes the test's
behaviour rather than a server-internal version label.

Author: Fivell

tests/resources/voice-in-trunks.test.ts

@@ -293,13 +293,13 @@ describe('TrunkConfiguration serialization', () => {
     });
 
     it('disable patch sends enabled_sip_registration:false + host + use_did_in_ruri:false together', async () => {
-      // The disable flow is a multi-field PATCH because the server's V3
-      // form rejects (422) any request that flips
+      // The disable flow is a multi-field PATCH because the server
+      // returns 422 for any request that flips
       // `enabled_sip_registration` to false without simultaneously
-      // providing a non-blank `host` (model-level presence) and
-      // `use_did_in_ruri: false` (form-level). Lock those three fields
-      // in the same request body — nock's body matcher rejects the
-      // request if any of them is missing or has the wrong value.
+      // providing a non-blank `host` and `use_did_in_ruri: false`.
+      // Lock those three fields in the same request body — nock's body
+      // matcher rejects the request if any of them is missing or has
+      // the wrong value.
       const client = setupClient('voice_in_trunks/disable_sip_registration.yaml');
       const result = await client.voiceInTrunks().update({
         id: '57a939dd-1600-41a6-80b1-f624e22a1f4c',