Fix three pre-publish issues found in readiness audit

- create_task.py list-tasks: crash on null credentials.provider
  (`creds.get("provider", {})` returns None when key exists but is null;
  switch to `(creds.get("provider") or {})`)

- sitecustomize.py: write hook_status.json after each module, not only
  when both have loaded; S3-only users (B2 module never imported) now
  get a status file from verify instead of "No status file found"

- README: add filesystem find + sqlite3 DB query to the emergency
  recovery section so users can locate their clone path when middlewared
  is down and midclt is unavailable

patch/create_task.py

@@ -141,7 +141,7 @@ def cmd_list_tasks(client, _args):
     print("─" * 60)
     for t in sorted(tasks, key=lambda x: x["id"]):
         creds = t.get("credentials") or {}
-        ptype = creds.get("provider", {}).get("type", "?")
+        ptype = (creds.get("provider") or {}).get("type", "?")
         enabled = "yes" if t.get("enabled") else "no"
         print(f"{t['id']:>4}  {enabled:<8}  {ptype:<14}  {t.get('description', '')}")