Category Detail "None" creates "<prefix>: All" instead of prefix-only group

[sbcrumb]

Describe the bug
When Category Detail is set to None - single group (prefix only, no categories), Lineuparr still appends All to the configured Channel Group Prefix.

For example, with the Channel Group Prefix set to Spectrum, the resulting Dispatcharr channel group is created as:

Spectrum: All

Based on the setting description, I would expect the group to simply be named:

Spectrum

To Reproduce
Steps to reproduce the behavior:

Open the Lineuparr plugin settings.
Set Channel Group Prefix to Spectrum.
Set Category Detail to None - single group (prefix only, no categories).
Save the settings.
Run the Lineuparr channel sync/full sync.
Check the resulting channel group in Dispatcharr.
The group is created as Spectrum: All instead of Spectrum.

Expected behavior
When Category Detail is set to None - single group (prefix only, no categories), the resulting group should use only the configured prefix.

For example:

Spectrum

rather than:

Spectrum: All

The other Category Detail modes could still create category-specific groups such as Spectrum: Movies, Spectrum: Sports, etc.

Screenshots
Screenshot attached showing:

Channel Group Prefix: Spectrum
Category Detail: None - single group (prefix only, no categories)
Resulting Dispatcharr group: Spectrum: All

Desktop (please complete the following information):

OS: Windows
Browser: Chrome
Lineuparr: current plugin version
Dispatcharr: 0.31.0

Smartphone (please complete the following information):

N/A

Additional context
Looking at the plugin code, Category Detail = none appears to collapse all channels into a synthetic All category:

if detail == "none":
all_channels = []
for channels in original_cats.values():
all_channels.extend(channels)
result["categories"] = {"All": all_channels}

That All category is then passed to _make_group_name(), which combines it with the configured prefix:

if prefix:
if prefix[-1] in ":_-/ ":
return f"{prefix}{category}"
return f"{prefix}: {category}"

This appears to be why Spectrum becomes Spectrum: All. Since the UI specifically describes the None option as "prefix only, no categories", it seems the synthetic All category should not be included in the final group name. Happy to fork and open a PR for this if you want.

[PiratesIRC]

Thanks for the clear report and for tracing it to the code. You are right:
with Category Detail set to None, _apply_category_detail puts every channel
into a single category called All, and _make_group_name then adds it after
the prefix, which gives Spectrum: All. The setting description says "prefix
only", so that is a bug.

I would welcome a pull request. Before you start, there are three things the
fix needs to handle. They are the reason this is more than a one-line change.

1. Lineuparr finds its own groups by rebuilding their names. At least eight
   places call _make_group_name(prefix, category) to work out which channel
   groups Lineuparr manages, including the cleanup of unmatched channels and
   the stream re-sort. If only the sync step changes the name, those places
   stop finding the group. Please make the change inside _make_group_name
   (or in one helper that every caller uses), so that everything agrees on the
   name.
2. People already using this mode have a <prefix>: All group. After the
   fix, their next sync would create a new Spectrum group, and the old
   Spectrum: All group would no longer be recognized as Lineuparr's. I would
   like the sync to rename the existing group when it finds <prefix>: All
   and no <prefix> group yet, rather than leave a duplicate behind. If both
   groups already exist, leave them alone and log a warning.
3. Two edge cases on the prefix. With no prefix at all, the group still
   needs a name, so keep All there. With a prefix that ends in a separator,
   such as DTV-, the group should probably be DTV rather than DTV-, so
   strip the trailing separator and any trailing space.

Please add a test for each of those, plus one confirming the other Category
Detail modes still produce Spectrum: Movies and so on. The test suite in
tests/ runs on pull requests, and .github/scripts/validate_plugin.py should
pass as well.