Name the option a refused address came from, and the data a 0.5.0 consumer stored

docs/decisions.md

@@ -480,19 +480,25 @@ rule and an index of the titles below.
 
 - **Every text field on the wire is latin1, and what the field cannot carry is refused rather than
   truncated.** Maintainer's call, 2026-09-21, the refusals from the security and stability passes on
-  [#16](https://gitea.larvit.se/larvit/smpp-js/pulls/16). Goal 3 settles the alphabet: 3.4 calls
-  these fields ASCII, and an operator routing an alphanumeric sender through the upper half is
-  traffic to keep, so the read is latin1 and the write is named latin1 to match — which is what
-  makes the round trip idempotent, and is already the octets Node put on the wire, so no peer sees a
-  change. Goal 2 settles the refusals, both of them a `size()` that would have agreed with a
+  [#16](https://gitea.larvit.se/larvit/smpp-js/pulls/16). 3.4 calls these fields ASCII, so goal 3
+  settles the read alone — its generous clause is scoped to reading, and its sender clause is strict.
+  Goal 1 settles the write, being 3.4 as SMSCs actually run it: an operator routing an alphanumeric
+  sender through the upper half is traffic to keep, and Node's `ascii` write already emitted the low
+  octet, so `Kaffeé` went out as `4B 61 66 66 65 E9` before this change and goes out as the same
+  octets after it. Naming the write latin1 is what makes the round trip idempotent, and no peer sees
+  a change. Goal 2 settles the refusals, both of them a `size()` that would have agreed with a
   `write()` that put something else on the wire: a character past `U+00FF` written as its low octet,
   and a caller's own `U+0000`, which the peer reads as the end of the field, shifting every mandatory
-  field behind it under a `command_length` that counted the whole string. `wantText()` and
+  field behind it under a `command_length` that counted the whole string. Goal 4 settles them twice
+  over, since for `一`, `　` and most emoji that low octet is `0x00` and the field went out malformed
+  on the operator's parser. `wantText()` and
   `wantCstringText()` are the only two places that decide it, which is why the `dest_address` and
   `unsuccess_sme` structures write their embedded addresses through `cstring.write()` rather than
   reaching past it into `writeCstring()`. Rejected: reading latin1 and leaving the write spelled
   ASCII, which leaves two halves agreeing only by accident. Rejected: refusing the upper half on send
-  to stay strict to 3.4's ASCII, which would drop exactly the traffic the read keeps. Rejected:
+  to stay strict to 3.4's ASCII, which would be a new restriction taking away traffic this library
+  already sends and operators already accept, on no defect; whether an SMSC wants a non-ASCII sender
+  stays its own call, answered as `ESME_RINVSRCADR`. Rejected:
   refusing `U+0000` in every text field, which would buy one spelling by taking a legitimate octet
   away from the length-prefixed Octet String, whose length octet is what ends it.