Missing image flags for Slovak and other already-recognized languages

[lubosve]

Description

JellyTag correctly detects Slovak audio language, but when the Language panel is configured to use Image/SVG badges, no Slovak flag is displayed.

Text mode works and shows SK.

Looking through the source, this appears to affect several languages that are already present in BadgeDisplayText, but are missing from KnownFlagCodes.

Slovak example

QualityDetectionService.cs already normalizes the legacy Slovak ISO code:
{ "slo", "slk" }

and ImageOverlayService.cs already contains:
{ "slk", "SK" }, { "slo", "SK" }

However, slk is missing from KnownFlagCodes.

Therefore:
slo → slk → not found in KnownFlagCodes → ResourceFileName = ""

There also appears to be no Assets/flag-slk.svg.

Other affected languages

These languages are present in BadgeDisplayText but not in KnownFlagCodes:
ell — Greek (gre → ell)
hrv — Croatian
srp — Serbian
bul — Bulgarian
slk — Slovak (slo → slk)
lit — Lithuanian
lav — Latvian
est — Estonian

Expected behavior

When an audio stream has:
Language: slk

or:
Language: slo

JellyTag should display the Slovak flag when Language badge style is set to Image.

The same should apply to the other supported languages listed above.

Possible fix

Add the missing canonical codes to KnownFlagCodes, for example:
"ell", "hrv", "srp", "bul", "slk", "lit", "lav", "est"

and add the corresponding flag-{code}.svg assets where they are currently missing.

The existing alias normalization can remain as-is.

Environment

JellyTag 2.0.2.0
Jellyfin 10.11.6

[eagleeyetom]

Hi,
I've created a fork of this project and tinkered with it a bit. Can you plase check this realease https://github.com/eagleeyetom/jellyfin-plugins/releases/tag/jellytag-2.3.0.0-beta ?