[ISSUE] Conflig flow hangs when performing getUsers on Matter lock (Ultraloq Bolt SE)

Start at the config flow's slot-occupancy read and trace how Matter getUser responses determine the next slot. Compare that behavior with the native matter.get_lock_users result and inspect the timeout budgets discussed in #1528 and #1536. Done means the flow completes for this lock, creates the config entry and entities, and cannot spin indefinitely.

What happened?

Config flow hangs forever on a Matter lock: slot occupancy read stops after slot 1

Summary

On a Matter lock, the config flow's slot-occupancy read issues exactly one
getUser (userIndex 1), then stalls indefinitely. The flow never advances, no
config entry or entities are created, and nothing is logged — not even with
custom_components.lock_code_manager at debug. There appears to be no deadline
on the operation: it has been spinning for 25+ minutes.

Environment

• Home Assistant Core 2026.9.2 (HAOS 18.2, frontend 20260826.7)
• Lock Code Manager 6.0.0 (HACS)
• Matter Server add-on 1.4.0 (matter.js 0.17.9)
• Lock: ULTRALOQ Bolt SE, firmware 01.54.0043 (Matter software version 50),
  Matter over Thread via the OpenThread Border Router add-on + SMLIGHT SLZB-06U
• Lock is healthy: reachable, ~1s event latency, 2-3s command round trips

Steps to reproduce

1. Fresh install of LCM 6.0.0, no prior config entry.
2. Add integration -> name + select the Matter lock entity -> Choose Path: YAML.
3. Paste a block of four users (name + quoted pin + enabled: true).
4. Flow moves to "Configure users" with the "reading which slots your locks
   already hold" message and a spinner.

Expected

The slot walk reads the lock's occupancy (all slots are free) and the entry is
created with four users.

Actual

One read, then silence. From the Matter Server add-on log:

15:47:36.162 Invoke >> 1.doorLock.getUser with userIndex: 1
15:47:38.036 Invoke << 1.doorLock.getUser userIndex: 1 userName: null
             userStatus: null userType: null credentialRule: null
             credentials: null nextUserIndex: null

No further getUser, setUser or setCredential calls were issued in the
following 25 minutes. config_entries has no lock_code_manager entry and the
entity registry has no lock_code_manager entities.

The lock's user table is empty and readable through HA's own action --
matter.get_lock_users returns {"max_users": 10, "users": []} in about two
seconds, and HA's native Matter "Manage Users" dialog reads and writes the same
table without trouble.

Suspected cause

This lock returns nextUserIndex: null on every getUser response, including
reads issued by HA's native Matter dialog. If the slot walk follows
nextUserIndex to find the next slot to read, it receives null and waits rather
than continuing. Iterating 1..NumberOfTotalUsersSupported (10 on this lock)
would avoid the dependency on an optional field.

Note also that no operation deadline appears to fire -- 25+ minutes with the
flow still open -- despite the budgets described in #1528/#1536.

Secondary notes

1. Taking the UI path instead of YAML, the flow reaches step code_slot
   server-side (HA returns a valid form: name, pin, enabled, condition, titled
   "User 1 of 2") but the dialog renders only a spinner in one browser profile.
   The YAML path rendered fine in the same session, so this may be a separate
   frontend issue, or may be environmental -- reported here only for context.

2. Documentation conflict: the num_users step says LCM will read which slots
   the locks already hold, while other guidance says to clear all slots before
   setup. On a write-only provider like Matter it is unclear which applies.

Steps to reproduce the issue

...

Home Assistant Version

2026.9.2

What version of Lock Code Manager are you running?

6.0.0

Lock make and model

Ultraloq Bolt SE

Debug logs (paste)

Debug logs (upload)

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Lock Code Manager diagnostics (upload)

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Lock integration diagnostics (upload)

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Diagnostics (paste)

Browser console logs (paste)

Browser console logs (upload)

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Screenshots

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Anything else?

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