[Test PR] Desktop fix and unoconv to unoserver (#2971)

# Description of Changes

This pull request includes several updates to the Docker configuration
and Java application UI scaling. The changes enhance environment
variable management, dependency installation, and UI responsiveness to
different screen sizes.

### Docker Configuration Updates:
* Added new environment variables `STIRLING_PDF_DESKTOP_UI`,
`PYTHONPATH`, `UNO_PATH`, and `URE_BOOTSTRAP` to `Dockerfile` and
`Dockerfile.fat` to improve the configuration and integration of the
LibreOffice environment.
[[1]](diffhunk://#diff-dd2c0eb6ea5cfc6c4bd4eac30934e2d5746747af48fef6da689e85b752f39557L38-R46)
[[2]](diffhunk://#diff-571631582b988e88c52c86960cc083b0b8fa63cf88f056f26e9e684195221c27L40-R49)
* Updated the `CMD` instruction in `Dockerfile` and `Dockerfile.fat` to
run both the Java application and `unoserver` simultaneously.
[[1]](diffhunk://#diff-dd2c0eb6ea5cfc6c4bd4eac30934e2d5746747af48fef6da689e85b752f39557L87-R96)
[[2]](diffhunk://#diff-571631582b988e88c52c86960cc083b0b8fa63cf88f056f26e9e684195221c27L87-R100)
* Modified the `RUN` instruction to include additional Python
dependencies and setup a virtual environment.
[[1]](diffhunk://#diff-dd2c0eb6ea5cfc6c4bd4eac30934e2d5746747af48fef6da689e85b752f39557L68-R81)
[[2]](diffhunk://#diff-571631582b988e88c52c86960cc083b0b8fa63cf88f056f26e9e684195221c27R72-R86)

### Workflow Enhancements:
* Added `STIRLING_PDF_DESKTOP_UI` environment variable to the GitHub
Actions workflows (`PR-Demo-Comment.yml` and `push-docker.yml`) to
ensure consistent environment settings.
[[1]](diffhunk://#diff-145fe5c0ed8c24e4673c9ad39800dd171a2d0a2e8050497cff980fc7e3a3df0dR106)
[[2]](diffhunk://#diff-76056236de05155107f6a660f1e3956059e37338011b8f0e72188afcb9b17b6fR41)

### Java Application UI Scaling:
* Introduced `UIScaling` utility to dynamically adjust the size of UI
components based on screen resolution in `DesktopBrowser` and
`LoadingWindow` classes.
[[1]](diffhunk://#diff-dff83b0fe53cba8ee80dc8cee96b9c2bfec612ec1f2c636ebdf22dedb36671e8L218-R219)
[[2]](diffhunk://#diff-dff83b0fe53cba8ee80dc8cee96b9c2bfec612ec1f2c636ebdf22dedb36671e8L267-R270)
[[3]](diffhunk://#diff-3e287daf297213b698b3c94d6e6ed4aae139d570ba6b115da459d72b5c36c42fL44-R64)
[[4]](diffhunk://#diff-3e287daf297213b698b3c94d6e6ed4aae139d570ba6b115da459d72b5c36c42fL86-R102)
* Improved the loading of icons by using the `UIScaling` utility for
better visual quality.

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] 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)
- [ ] I have performed a self-review of my own code
- [ ] 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.

---------

Co-authored-by: pixeebot[bot] <104101892+pixeebot[bot]@users.noreply.github.com>
Co-authored-by: a <a>

Dockerfile.fat

@@ -9,6 +9,7 @@ COPY . .
 
 # Build the application with DOCKER_ENABLE_SECURITY=false
 RUN DOCKER_ENABLE_SECURITY=true \
+STIRLING_PDF_DESKTOP_UI=false \
 ./gradlew clean build
 
 # Main stage
@@ -37,12 +38,15 @@ ENV DOCKER_ENABLE_SECURITY=false \
     PGID=1000 \
     UMASK=022 \
     FAT_DOCKER=true \
-    INSTALL_BOOK_AND_ADVANCED_HTML_OPS=false
+    INSTALL_BOOK_AND_ADVANCED_HTML_OPS=false \
+    PYTHONPATH=/usr/lib/libreoffice/program:/opt/venv/lib/python3.12/site-packages \
+    UNO_PATH=/usr/lib/libreoffice/program \
+    URE_BOOTSTRAP=file:///usr/lib/libreoffice/program/fundamentalrc
 
 
 # JDK for app
-RUN echo "@testing https://dl-cdn.alpinelinux.org/alpine/edge/main" | tee -a /etc/apk/repositories && \
-    echo "@testing https://dl-cdn.alpinelinux.org/alpine/edge/community" | tee -a /etc/apk/repositories && \
+RUN echo "@main https://dl-cdn.alpinelinux.org/alpine/edge/main" | tee -a /etc/apk/repositories && \
+    echo "@community https://dl-cdn.alpinelinux.org/alpine/edge/community" | tee -a /etc/apk/repositories && \
     echo "@testing https://dl-cdn.alpinelinux.org/alpine/edge/testing" | tee -a /etc/apk/repositories && \
     apk upgrade --no-cache -a && \
     apk add --no-cache \
@@ -65,14 +69,21 @@ RUN echo "@testing https://dl-cdn.alpinelinux.org/alpine/edge/main" | tee -a /et
 # OCR MY PDF (unpaper for descew and other advanced featues)
         qpdf \
         tesseract-ocr-data-eng \
+        
         font-terminus font-dejavu font-noto font-noto-cjk font-awesome font-noto-extra \
 # CV
 		py3-opencv \
-# python3/pip
-        python3 \
-    py3-pip && \
-# uno unoconv and HTML
-    pip install --break-system-packages --no-cache-dir --upgrade unoconv WeasyPrint pdf2image pillow && \
+    python3 \
+    py3-pip \
+    py3-pillow@testing \
+    py3-pdf2image@testing && \
+    python3 -m venv /opt/venv && \
+    export PATH="/opt/venv/bin:$PATH" && \
+    pip install --upgrade pip && \
+    pip install --no-cache-dir --upgrade unoserver weasyprint && \
+    ln -s /usr/lib/libreoffice/program/uno.py /opt/venv/lib/python3.12/site-packages/ && \
+    ln -s /usr/lib/libreoffice/program/unohelper.py /opt/venv/lib/python3.12/site-packages/ && \
+    ln -s /usr/lib/libreoffice/program /opt/venv/lib/python3.12/site-packages/LibreOffice && \
     mv /usr/share/tessdata /usr/share/tessdata-original && \
     mkdir -p $HOME /configs /logs /customFiles /pipeline/watchedFolders /pipeline/finishedFolders && \
     fc-cache -f -v && \
@@ -84,7 +95,6 @@ RUN echo "@testing https://dl-cdn.alpinelinux.org/alpine/edge/main" | tee -a /et
     chown stirlingpdfuser:stirlingpdfgroup /app.jar
 
 EXPOSE 8080/tcp
-
 # Set user and run command
 ENTRYPOINT ["tini", "--", "/scripts/init.sh"]
-CMD ["java", "-Dfile.encoding=UTF-8", "-jar", "/app.jar"]
+CMD ["sh", "-c", "java -Dfile.encoding=UTF-8 -jar /app.jar & /opt/venv/bin/unoserver --port 2003 --interface 0.0.0.0"]