fix(spelling): correct selectFilter typo across templates and localization files (#3886)

# Description of Changes

- **What was changed**  
- Renamed all occurrences of the misspelled key `selectFillter` to
`selectFilter` in HTML templates (`team-details.html`,
`adminSettings.html`, `cert-sign.html`) and in every locale properties
file under `stirling-pdf/src/main/resources/messages_*.properties`.
- Removed obsolete `WorkInProgess` entries from various locale files.

- **Why the change was made**  
To fix a consistent spelling mistake in the UI select placeholder key,
ensuring that the label displays correctly and translations resolve
properly.

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.

stirling-pdf/src/main/resources/messages_en_GB.properties

@@ -163,7 +163,7 @@ alphabet=Alphabet
 downloadPdf=Download PDF
 text=Text
 font=Font
-selectFillter=-- Select --
+selectFilter=-- Select --
 pageNum=Page Number
 sizes.small=Small
 sizes.medium=Medium
@@ -174,7 +174,7 @@ error.pdfCorrupted=PDF file appears to be corrupted or damaged. Please try using
 error.pdfCorruptedMultiple=One or more PDF files appear to be corrupted or damaged. Please try using the 'Repair PDF' feature on each file first before attempting to merge them.
 error.pdfCorruptedDuring=Error {0}: PDF file appears to be corrupted or damaged. Please try using the 'Repair PDF' feature first to fix the file before proceeding with this operation.
 
-# Frontend corruption error messages  
+# Frontend corruption error messages
 error.pdfInvalid=The PDF file "{0}" appears to be corrupted or has an invalid structure. Please try using the 'Repair PDF' feature to fix the file before proceeding.
 error.tryRepair=Try using the Repair PDF feature to fix corrupted files.
 
@@ -192,7 +192,7 @@ error.optionsNotSpecified={0} options are not specified
 error.fileFormatRequired=File must be in {0} format
 error.invalidFormat=Invalid {0} format: {1}
 error.endpointDisabled=This endpoint has been disabled by the admin
-error.urlNotReachable=URL is not reachable, please provide a valid URL  
+error.urlNotReachable=URL is not reachable, please provide a valid URL
 
 # DPI and image rendering messages - used by frontend for dynamic translation
 # Backend sends: [TRANSLATE:messageKey:arg1,arg2] English message
@@ -242,7 +242,6 @@ red=Red
 green=Green
 blue=Blue
 custom=Custom...
-WorkInProgess=Work in progress, May not work or be buggy, Please report any problems!
 poweredBy=Powered by
 yes=Yes
 no=No