fix(lotus): explain a failed voice connection and offer Try again

"Failed to connect to Livekit server (Reason: ServerUnreachable)" left a
user with nothing to try; they retried for a long time and gave up.

- Title "Couldn't connect to voice". The message depends on the reason:
  unreachable/timeout-style errors explain that voice needs its own live
  connection, which VPNs, antivirus web shields and some networks block,
  even when chat works, and say what to try; NotAllowed says the call may
  be full or access changed.
- The raw reason, status and message move under Technical details.
- LivekitConnectionError and PeerConnectionTimeoutError now get a
  Try again button (the existing reconnect path), shown as primary: the
  Lotus theme renders `secondary` as dark-on-dark.

Verified in the Lotus client against a local LiveKit with the signal
socket and validate request blocked: the dialog appears after ~20 s;
unblocking and pressing Try again joins with the mic published.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

locales/en/app.json

@@ -104,8 +104,9 @@
     "generic_description": "Submitting debug logs will help us track down the problem.",
     "insufficient_capacity": "Insufficient capacity",
     "insufficient_capacity_description": "The server has reached its maximum capacity and you cannot join the call at this time. Try again later, or contact your server admin if the problem persists.",
-    "livekit_connection_error": "Failed to connect to Livekit server",
-    "livekit_connection_error_description": "An error occurred while connecting to the Livekit server (<1>Reason:</1> <2>{{ reason }}</2>).",
+    "livekit_connection_error": "Couldn’t connect to voice",
+    "livekit_not_allowed_description": "The voice server didn’t let you in. The call may be full, or your access to this room may have changed. Try again in a moment.",
+    "livekit_unreachable_description": "Your device couldn’t reach the voice server. Chat can still work when this happens: voice needs its own live connection, which VPNs, antivirus web protection and some work or school networks block. Try again. If it keeps failing, pause your VPN or antivirus web shield, or try another network such as a phone hotspot.",
     "matrix_rtc_transport_missing": "The server is not configured to work with {{brand}}. Please contact your server admin (Domain: {{domain}}, Error Code: {{ errorCode }}).",
     "membership_manager": "Membership Manager Error",
     "membership_manager_description": "The Membership Manager had to shut down. This is caused by many consecutive failed network requests.",
@@ -119,6 +120,7 @@
     "sfu_token_refused": "Can't join this call",
     "sticky_events_required": "Homeserver does not support Matrix 2.0 calls",
     "sticky_events_required_description": "This deployment is configured to use Matrix 2.0 call mode, but the homeserver does not advertise support for sticky events (MSC4354). Ask your server admin to upgrade, or switch the deployment to a compatible mode.",
+    "try_again": "Try again",
     "unexpected_ec_error": "An unexpected error occurred (<0>Error Code:</0> <1>{{ errorCode }}</1>). Please contact your server admin."
   },
   "group_call_loader": {