chore: update PDFBox to 3.0.7 (#4)

Bumps Apache PDFBox from 3.0.5 to 3.0.7.

Validation:
- mvn clean test (672 tests pass)
- mvn clean verify (full canonical gate)
- All 30 example PDFs regenerated successfully
- Visual regression tests (PdfVisualRegressionTest, ShapeContainerVisualRegressionTest) pass against committed baselines

Author: DemchaAV

pom.xml

@@ -52,7 +52,7 @@
         <kotlin.version>2.2.20</kotlin.version>
         <logback.version>1.5.18</logback.version>
         <lombok.version>1.18.38</lombok.version>
-        <pdfbox.version>3.0.5</pdfbox.version>
+        <pdfbox.version>3.0.7</pdfbox.version>
         <poi.version>5.4.0</poi.version>
         <javafx.version>21.0.2</javafx.version>
         <slf4j.version>2.0.17</slf4j.version>