v3.28.3: the outfile ADM byte-pair rule

The review of v3.28.2 found the parser accepting an odd-length ADM (e.g.
12345), while /api/verify-adm requires byte pairs
((?:[0-9A-F]{2}){2,8}) - the stored value could never verify and was
refused with a misleading "adm must be 4-16 hex digits".

The parser now applies the verifier's exact rule: an odd length (a half
byte) or a value over 16 digits is dropped at import time with "ADM is
not 4-16 hex digits in byte pairs".

Docs: help EN/RU, api.md and the repo AGENTS say "4-16 hex digits in
byte pairs".  Tests: the odd-length and the over-16 drop cases (both
real samples are even-length and unaffected: BAP 3632333239463337,
AM0027 CFA3DD9C6B7F0F8C).  915 frontend + 925 Python; sw cache
simple-v441.

frontend/index.html

@@ -1910,7 +1910,7 @@
 // ===== Version =====
 // Single source of truth for the PWA version: shown in the header and used
 // by the server version check in pysimConnect().
-const SIMPLE_VERSION = '3.28.2';
+const SIMPLE_VERSION = '3.28.3';
 document.getElementById('app-version').textContent = 'v' + SIMPLE_VERSION;
 
 // ===== view history (the browser Back/Forward buttons) =====