fix: daemon lifecycle cleanup and error logging improvements

- Refactor HealthDaemon to use a tracked session (AbortController + awaitable
  promise) instead of fire-and-forget health check loops, preventing health
  checks from running after a service is stopped
- Stop health checks before terminating daemon to avoid false crash reports
  during intentional shutdown
- Guard onExit callbacks with AbortSignal to prevent stale session callbacks
- Add logErrorOnce utility to deduplicate repeated error logging
- Fix SystemForEmbassy.stop() to capture clean promise before deleting ref
- Treat SIGTERM (signal 15) as successful exit in subcontainer sync
- Fix asError to return original Error instead of wrapping in new Error
- Remove unused ExtendedVersion import from Backups.ts

sdk/base/lib/util/asError.ts

@@ -8,7 +8,7 @@
  */
 export const asError = (e: unknown) => {
   if (e instanceof Error) {
-    return new Error(e as any)
+    return e
   }
   if (typeof e === 'string') {
     return new Error(`${e}`)

sdk/base/lib/util/index.ts

@@ -32,3 +32,4 @@ export { deepEqual } from './deepEqual'
 export { AbortedError } from './AbortedError'
 export * as regexes from './regexes'
 export { stringFromStdErrOut } from './stringFromStdErrOut'
+export { logErrorOnce } from './logErrorOnce'

sdk/base/lib/util/logErrorOnce.ts

@@ -0,0 +1,9 @@
+const loggedErrors = new WeakSet<object>()
+
+export function logErrorOnce(err: unknown) {
+  if (typeof err === 'object' && err !== null) {
+    if (loggedErrors.has(err)) return
+    loggedErrors.add(err)
+  }
+  console.error(err)
+}