release: v3.9.0 - the operation start buttons wait for a preset and a keyset

Gating: the SCP80 "Send to Card", the RAM Execute and the TAR-probe Execute
buttons carry `data-needs-keyset`; pysimApplyAvailability() disables them
(with the hint "Select a card preset and its keyset" when the card itself is
fine) unless the view's preset is selected and the form's keyset number is one
of its keysets - `spKeysetStartReady`, the same rule the click-time guards
enforce, which stay as the last line of defence.  spKeysetSync() refreshes the
gate on every preset/keyset change, and the KIc/KID index selects now call
spKeysetSync() so the keyset selector follows a manual index change too.

Version 3.9.0: server VERSION, pyproject.toml and the PWA header; sw cache
simple-v346; the workspace AGENTS gains its v3.9.0 history entry.

Tests: indicator.test.js drives the gate (no preset -> disabled with the hint,
an undefined keyset -> disabled, a matching keyset -> enabled) and guards the
three buttons' attribute; the cards/keysets/ram sandboxes stub
pysimApplyAvailability.  Help EN/RU notes the disabled start buttons.

pysim_simple_server/server.py

@@ -32,7 +32,7 @@ from osmocom.tlv import BER_TLV_IE
 from osmocom.utils import rpad
 
 
-VERSION = '3.8.0'
+VERSION = '3.9.0'
 
 MAX_ENVELOPE_SEGMENTS = 5  # max SMS segments for outgoing C-APDU in ENVELOPE