Wrap original get_restic_config instead of replacing it; add hook status file

sitecustomize.py: _patch_restic no longer reimplements get_restic_config.
It now wraps the original: calls _orig(cloud_backup) to get a ResticConfig,
then post-processes only the -r argument to fix "b2:/bucket" → "b2:bucket"
when the URL contains a stray leading slash (the stock bug for empty-hostname
providers). Uses dataclasses.replace() to build the corrected result so new
ResticConfig fields added in future TrueNAS versions pass through unchanged.
This eliminates the transfer_setting gap, env dict mutation, and frozen-copy
drift that would occur over time.

Also adds a status file mechanism: sitecustomize.py writes
/data/truecloud-patch/hook_status.json atomically after both patches have
reported success or failure. This gives a machine-readable signal that the
hook fired correctly — without requiring log scraping.

create_task.py: new "verify" subcommand reads the status file and prints a
human-readable summary. Does not require --host or --api-key. --host and
--api-key are now optional at the parser level and validated only for
subcommands that actually need an API connection.

README: update troubleshooting to use "create_task.py verify" instead of
the manual Python introspection one-liner.

README.md

@@ -206,11 +206,11 @@ cat /data/truecloud-patch/apply.log
 
 **Verify backend patch is loaded** (while middlewared is running):
 ```bash
-python3 -c "
-from middlewared.rclone.remote.b2 import B2RcloneRemote
-print('B2 restic support:', hasattr(B2RcloneRemote, 'get_restic_config'))
-"
+python3 /data/truecloud-patch/create_task.py verify
 ```
+This reads `/data/truecloud-patch/hook_status.json`, written by the import hook
+at middlewared startup. It shows which patches applied and any failure details.
+Does not require `--host` or `--api-key`.
 
 **Verify the UI patch** (should print your TrueNAS version):
 ```bash