[Bug]: KIO worker socket error ("Can not create a socket for launching a KIO worker for protocol 'tags'") in native Dolphin (non-portal) under Niri

### Kernel

7.2.3-1-cachyos

### Desktop Environment / Window Manager

Niri (not Plasma) - native Dolphin, not launched via xdg-desktop-portal-kde

### CPU

Not relevant to this issue.

### GPU / Driver

Not relevant to this issue.

### Description

Opening `tags:/` or `trash:/` in a plain, native Dolphin window (not via xdg-desktop-portal-kde, no Plasma session involved) immediately fails with:

> Unable to create KIO worker.
> Can not create a socket for launching a KIO worker for protocol 'tags'.

This looks related to #372 but is a distinct case: that issue was scoped to portal apps under a full Plasma session (kioworker/kded/systemsettings profiles), and reporters there said "native non-portal KDE apps (Dolphin, Kate) work fine". In my case it's the opposite: Dolphin itself, run directly (no portal involved), fails natively.

**Root cause traced via strace:** KIO's `ConnectionServer::listenForRemote()` creates the worker socket file via the standard atomic-rename pattern: `openat(dir, O_TMPFILE|O_RDWR|O_CLOEXEC)` followed by `linkat(AT_FDCWD, "/proc/self/fd/N", AT_FDCWD, "/dolphin..kioworker.socket", AT_SYMLINK_FOLLOW)`. On this system the `linkat` call consistently fails with `ENOENT`, retried ~15 times with fresh random names each time, then Dolphin gives up:

```
ConnectionServer::listenForRemote failed: "QLocalServer::listen: Name error"
KIO Connection server not listening, could not connect
couldn't create worker: "Can not create a socket for launching a KIO worker for protocol 'tags'."
```

The `dolphin` AppArmor profile audit log shows the corresponding `link` operation as `ALLOWED`, but with `info="Failed name lookup - deleted entry" error=-2` (i.e. ENOENT) right before it - AppArmor's own path-resolution for the `link` LSM hook appears to choke on the anonymous/unlinked `O_TMPFILE` dentry (it has no stable path by design), and this seems to corrupt the underlying syscall's outcome even though the final verdict is ALLOW, not DENY.

**Confirmed by testing all three enforcement modes:**
- `enforce` (default): fails, every time
- `complain` (`aa-complain dolphin`): **fails identically** - this rules out a plain permission denial, since complain mode never blocks anything
- fully unconfined (`aa-disable dolphin`): **works immediately**, both `tags:/` and `trash:/` open normally

Reproducing the exact same `openat(dir, O_TMPFILE|O_RDWR|O_CLOEXEC)` + `linkat(AT_FDCWD, "/proc/self/fd/N", ...)` syscall pair standalone (plain Python script, same target directory, same filename pattern) succeeds every time - so this isn't a kernel/tmpfs limitation in general, only something about how AppArmor mediates it in the context of Dolphin's confined process.

As a side effect, this also explains a second, seemingly unrelated symptom: Dolphin's Trash places-panel icon always showed as "full" regardless of actual trash contents, because the `trash:/` KIO worker could never be created to report the real state either. Fixed at the same time as `tags:/`.

### Steps to Reproduce

1. `pkill -x dolphin` (ensure no running instance)
2. `dolphin tags:/` (fresh process, not delegated via D-Bus to an existing window)
3. Observe the error dialog immediately

### Expected Behavior

`tags:/` and `trash:/` open normally in Dolphin.

### Actual Behavior

Immediate error:

> Unable to create KIO worker.
> Can not create a socket for launching a KIO worker for protocol 'tags'.

Trash icon in the places panel permanently shows as full.

### Logs / Error Messages

strace excerpt (full trace available on request):
```
openat(AT_FDCWD, "/run/user/1000", O_RDWR|O_CLOEXEC|O_TMPFILE, 0600) = 44
linkat(AT_FDCWD, "/proc/self/fd/44", AT_FDCWD, "/run/user/1000/dolphinxPWiOm.83.kioworker.socket", AT_SYMLINK_FOLLOW) = -1 ENOENT (No such file or directory)
[... 14 more identical attempts with fresh random names, all ENOENT ...]
```

journalctl:
```
ConnectionServer::listenForRemote failed: "QLocalServer::listen: Name error"
KIO Connection server not listening, could not connect
couldn't create worker: "Can not create a socket for launching a KIO worker for protocol 'trash'."
couldn't create worker: "Can not create a socket for launching a KIO worker for protocol 'tags'."
```

AppArmor audit (kernel log), same operation:
```
apparmor="ALLOWED" operation="link" class="file" info="Failed name lookup - deleted entry" error=-2 profile="dolphin" name="/run/user/1000/#1094" pid= comm="dolphin" requested_mask="l" denied_mask="l" fsuid=1000 ouid=1000
apparmor="ALLOWED" operation="link" class="file" profile="dolphin" name="/run/user/1000/dolphinbFLNbr.88.kioworker.socket" pid= comm="dolphin" requested_mask="l" denied_mask="l" fsuid=1000 ouid=1000 target="/run/user/1000/#1094"
```

### Additional Context

Package versions:
```
qt6-base 6.11.2-3.1
kio 6.29.0-2.1
kio-extras 26.08.0-1.1
dolphin 26.08.0-5.1
apparmor 4.1.7-1.1
apparmor.d 0.4912.0-1
```

The `dolphin` AppArmor profile already contains what looks like the correct rule for this exact socket pattern:
```
owner @{run}/user/@{uid}/dolphin@{rand6}.@{int}.kioworker.socket rwl -> @{run}/user/@{uid}/#@{int},
```
so this doesn't look like a missing-rule issue like #372 was - the rule is present and matches (audit log confirms ALLOWED), but the underlying syscall still fails, which points more toward an AppArmor/kernel LSM `path_link` hook bug when mediating `O_TMPFILE`-based atomic renames specifically, rather than a simple missing permission in the profile itself.

Happy to provide the full strace log or test further AppArmor tweaks if useful for tracking this down.

Reproduce the failure with a fresh native Dolphin process opening tags:/ or trash:/, then inspect KIO's ConnectionServer::listenForRemote behavior with strace and the dolphin AppArmor audit entries. Compare enforce, complain, and fully unconfined modes, including the O_TMPFILE/linkat sequence. Done means explaining the confined-process failure and validating a project change or a clearly documented blocker without breaking normal worker-socket creation.

Written by the indexing model from the issue text.