The contextSwitching early return in isRouteSessionMismatch sat above the
same-id short-circuit, so a profile or connection switch while the route
already pointed at the selected session reported a mismatch and blanked the
chat to the splash. On main that call returned false.
Move the selected-session check ahead of the contextSwitching guard: when the
selected view already owns the routed conversation there is no prior context
to leak, so nothing needs hiding. The guard still denies only the
transcript-retention fallback, which is the case it was added for.
Adds the exact regression to route-session-state.test.ts.
3c0dcbbdc7