feat(socket-auth): show channel authorization failures in the sockets viewer

[roncodes]

What

The Developers → Sockets viewer now shows when a channel subscription is refused. Before, it showed "Awaiting events..." forever. The same view handles channels opened from the Listen on custom channel modal, so that path is covered too.

• subscribeFail on the channel is logged in red:
  • An authorization refusal from the socket server (AuthError) reads "Not authorized to subscribe to channel {name} ({reason})". The reason is the server's short snake_case code, for example forbidden.
  • Any other failure reads "Could not subscribe to channel {name}: {message}".
  • After a refusal the "Awaiting events..." indicator is hidden.
• kickOut is logged as "Removed from channel {name} ({reason})". When the channel was lost for a token reason, the socket service in ember-core resubscribes it. The view then logs "Socket subscribed to channel..." again and clears the failure state.
• Output lines are built through a logEvent() helper, which reassigns the tracked array instead of calling pushObject.
• Event content is now rendered as escaped text with whitespace-pre-wrap, not through html-safe. The lines carry server-provided strings (refusal reasons, published payloads), so they should not be read as HTML. Pretty-printed JSON now keeps its line breaks.
• New strings are added to all 11 locales.

Why

This is the dev-engine part of the socket-auth work. Once the socket server enforces channel authorization, a channel the user may not see is refused. The viewer should say so rather than look broken.

Test plan

Verified by CI. tests/unit/controllers/sockets/view-test.js replaces the placeholder test with tests for:

• how refusals are described
• the refusal, kick-out and resubscribe sequence and the awaiting indicator
• JSON data output
• cleanup when leaving the page

Related PRs

Part of the authenticated realtime channels rollout (socket auth), one PR per repo:

• feat(socket-auth): authenticated realtime channels (tokens, authorizer, signed publish) core-api#290 — tokens, channel authorizer, signed HTTP publish (merge and tag first: fleetops and storefront require fleetbase/core-api ^1.6.69)
• feat(socket-auth): fleetops channel resolvers, driver socket tokens, per-customer tracking channel fleetops#358 — fleetops channel resolvers, driver socket tokens, per-customer tracking channel
• feat(socket-auth): storefront customer and checkout socket tokens, channel resolvers storefront#113 — customer and checkout socket tokens, storefront/checkout resolvers
• feat(socket-auth): Fleetbase socket server with JWT auth and signed internal publish fleetbase#704 — fleetbase/fleetbase-socket server, compose/helm/installer, console socket test page
• feat(socket-auth): authenticate the realtime socket with session socket tokens ember-core#97 — console socket service authenticates with session tokens
• feat(socket-auth): show channel authorization failures in the sockets viewer #51 — sockets viewer shows authorization failures
• feat(socket-auth): authenticate realtime socket with driver socket tokens navigator-app#112 — driver app socket tokens
• feat(socket-auth): authenticate realtime socket with customer and checkout socket tokens storefront-app#65 — customer and checkout socket tokens
• feat(socket-auth): generate the socket auth key on install fleetbase-cli#11 — installer generates the socket auth key
• feat(socket-auth): add socket.token() to mint realtime socket tokens fleetbase-js#45, feat(socket-auth): add customer.socketToken() for realtime channels storefront-js#22, feat(socket-auth): add socket->token() to mint realtime socket tokens fleetbase-php#28 — SDK socket token helpers
• docs(socket-auth): authenticated realtime channels and migration guide fleetbase.io#120 — docs and migration guide