feat(examples): a five-slide carousel sized for a LinkedIn document post

Portrait 1080x1350, which is the tallest frame LinkedIn shows without cropping,
so the type can be sized for a phone rather than a desktop preview. Five slides:
the one-composition premise, what the PPTX backend actually is, the comparative
numbers, the guarantees behind them, and how to depend on it.

Figures are read at render time - the version line from the filtered
banner.properties, the comparative timings from the committed benchmark
snapshot - so the file does not need remembering on the next release.

The coordinate slide deliberately does not print the reactor version: this
renders from a -SNAPSHOT tree, and publishing that string would advertise a
coordinate that is not on Central.

Two engine details the layout needed. A section measures to its longest line,
so a stack of cards renders with ragged right edges; a zero-height spacer sets
the width floor and they line up. Leading whitespace is trimmed during inline
layout, so the code sample indents with non-breaking spaces, which occupy the
same advance in a monospaced face.

The same composition also writes a PPTX, which is what keeps slide two's claim
about identical geometry honest whenever this file changes.

Author: DemchaAV

examples/src/main/java/com/demcha/examples/GenerateAllExamples.java

@@ -52,6 +52,7 @@
 import com.demcha.examples.flagships.FinancialReportPptxExample;
 import com.demcha.examples.flagships.MasterShowcaseExample;
 import com.demcha.examples.flagships.MasterShowcasePptxExample;
+import com.demcha.examples.flagships.LinkedInCarouselExample;
 import com.demcha.examples.flagships.SocialCardExample;
 import com.demcha.examples.flagships.MavenBannerPptxExample;
 import com.demcha.examples.flagships.ModuleFirstFileExample;
@@ -225,6 +226,8 @@ public static void main(String[] args) throws Exception {
         System.out.println("Generated: " + MavenBannerPptxExample.generate());
         System.out.println("Generated: " + SocialCardExample.generate());
         System.out.println("Generated: " + SocialCardExample.generatePptx());
+        System.out.println("Generated: " + LinkedInCarouselExample.generate());
+        System.out.println("Generated: " + LinkedInCarouselExample.generatePptx());
         System.out.println("Generated: " + TwinOutputExample.generate());
         System.out.println("Generated: " + FinancialReportExample.generate());
         System.out.println("Generated: " + FinancialReportPptxExample.generate());