fix(descriptor): rebuild SDP that Firefox accepts; release v5.8.1

Live cross-browser testing found three defects in the SBQ2 SDP template, all
invisible to Chrome and all fatal to Firefox.

The candidate lines omitted raddr/rport on srflx and relay candidates. RFC 8839
section 5.1 makes rel-addr and rel-port mandatory for non-host candidates even
though ICE never reads them; Chrome tolerates the omission and Firefox drops the
candidate. Relay-only connections to Firefox failed 0/8 against 8/8 for the
browser's own SDP. The STUN and TURN profiles hid it because a host pair
connected instead -- the relay candidates were never actually needed there.

The template also advertised ice-options:trickle without ever closing the
candidate set, though a descriptor is a complete one-shot set with no channel to
trickle over, and hard-coded the m= port and c= line to the 9 / 0.0.0.0 null
default candidate, which is the trickle convention for "nothing gathered yet".
Both are now correct: no trickle, an explicit a=end-of-candidates, and the most
publicly reachable candidate as the default.

All three are serializer-side and cost zero descriptor bytes; sizes are
unchanged at 98-149 bytes, QR version 6-8. Verified 48/48 across all 16
combinations of {Chrome, Firefox} squared and four network profiles, with every
relay-only pair now connecting over the relay.

dist/app-boot.js

@@ -19984,7 +19984,7 @@ var SecureMasterKeyManager = class {
 var import_NotificationIntegration = __toESM(require_NotificationIntegration());
 
 // package.json
-var version = "5.8.0";
+var version = "5.8.1";
 
 // src/components/ui/Header.jsx
 var APP_VERSION = `v${version}`;