scp81: UI framing options, permissive TLS, drop the Apache-header mimicry (v2.2.14)

Listener Options block (applied at Start, persisted in localStorage, Reset to
defaults): HTTP framing - chunked body, chunk size (0 = one TLS record),
keep-alive, Connection header, compact headers, Next-URI (unchecked = omit);
script framing - indefinite/definite Command Scripting template, CR tag,
targeted app; link events (now parsed on the common start path, so every mode
honors them). scp81OptionsFromForm() is unit-tested.

TLS is automatic: 'auto' (min 1.0, max 1.2 + :@SECLEVEL=0) is the new
default, all six PSK suites are offered and OpenSSL negotiates the highest;
the negotiated version/cipher is logged (tls-handshake) and reported as
version_seen/cipher_seen in /api/scp81/status, and a handshake failing for a
TLS/cipher reason logs tls-handshake-failed (post-handshake record errors
stay tls-error). tls_version/cipher/keylog/answer_delay stay as API-only pins.

Dropped the Apache-style header mimicry completely: no Date/Server/
X-Powered-By, no Content-Length-before-Content-Type ordering, no Content-Type
on 204 - the minimal response set is X-Admin-Protocol (+ X-Admin-Next-URI /
Targeted-Application), Content-Type on 200s, and Transfer-Encoding or
Content-Length per the chunked flag. Docs, help (EN/RU), READMEs and the
AGENTS notes updated; SW cache otaman-v180.

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'otaman-v179';
+const CACHE = 'otaman-v180';
 const URLS = [
   'index.html',
   'help.html',