Collapse duplicated setup across the suite into six shared helpers under
test/test_helpers/ and rewrite the 28 suites that were open-coding it:
http_fixtures.dart jsonResponse() for http.Response JSON stubs
library_tab_scaffold.dart pumps library tabs under their required ancestors
multi_server_fixtures.dart MultiServerProvider wiring for widget tests
playback_report_fakes.dart PlaybackReportCall + fake report sinks
profile_stack.dart production-shaped profile dependency graph
theme.dart testMonoTokens for fast-settling widget tests
Net -1245 lines with no change in coverage or assertions.
Keep a running companion-remote host's crypto identity in sync with the
active profile: subscribe to PlexHome/connection/join streams and rebuild
auth contexts (restarting the broadcast when they change) so a removed
home user or revoked borrowed connection stops controlling the host.
Serialize host start/stop/crypto-rebuild through a lifecycle lock, clean
up peer subscriptions before re-listening, and guard the replaced-client
onDone against clobbering the new client's session. Drop the context.mounted
guards that aborted an app-level host start, fix the DiscoveryView
init-flash/stuck-on-throw, and delete the dead initialize*Crypto helpers.
edde746