## Why
An account change can select different OpenTelemetry collector settings. The
long-running app server needs to stop exporting telemetry with the previous
account's configuration.
## What changed
- Rebuild and install the log, trace, and metrics exporters when authentication
changes, and shut down the previous provider without blocking the app server.
- Make cached global metrics clients and the tracing layer follow the replacement
provider so existing callers continue exporting through the current account's
configuration.
- Clear the cached cloud configuration loader after login and logout so telemetry
reloads from the new account context.
## Testing
- Add an app-server integration test that switches accounts and verifies logs,
traces, and metrics reach the new collector while trace context is preserved.
- Add a metrics test covering cached clients after provider replacement.
GitOrigin-RevId: a74359777a35edbee5bbe0b2baccc155074cb172
d9eac10406