fix(examples): the deck called the PPTX backend a manifest skeleton

render-pptx ships two backends: PptxSemanticBackend, the slide-safe skeleton,
and PptxFixedLayoutBackend, which implements FixedLayoutRenderer and is
discovered through FixedLayoutBackendProvider exactly as the PDF backend is.
The module table listed render-pptx as "manifest only" and the architecture
proof card said PPTX was a skeleton, contradicting the deck's own first page,
which already labels render-pptx "fixed layout", and the capability matrix,
which gives PPTX (fixed) a column beside PDF.

The deck is republished by this change, so it was about to carry that
understatement of the engine's own capability into the release assets again.

Author: DemchaAV

assets/readme/examples/engine-deck-v2.pdf

@@ -490,7 +490,7 @@ private static void architecturePage(SectionBuilder page) {
                     PALE_VIOLET, VIOLET);
             proofCard(row, "FIXED BACKEND SPI", "FixedLayoutBackendProvider and FontMetricsProvider are discovered by ServiceLoader.",
                     PALE_BLUE, BLUE);
-            proofCard(row, "SEMANTIC EXPORT", "DOCX is a working POI exporter; PPTX is a slide-safe manifest skeleton in 2.0.",
+            proofCard(row, "SEMANTIC EXPORT", "DOCX is a working POI exporter; PPTX carries a slide-safe skeleton beside its fixed backend.",
                     PALE_MINT, MINT);
         });
         page.addParagraph(p -> pageNote(p, "The renderer boundary is explicit; Android or another backend is an extension opportunity, not a shipped 2.0 claim."));
@@ -640,7 +640,7 @@ private static DocumentNode moduleMatrix() {
                 {"core", "authoring + model"},
                 {"render-pdf", "fixed PDF"},
                 {"render-docx", "semantic DOCX"},
-                {"render-pptx", "manifest only"},
+                {"render-pptx", "fixed PPTX"},
                 {"templates", "opt-in presets"},
                 {"testing", "snapshot tools"},
                 {"graph-compose", "PDF wrapper"},

assets/readme/examples/engine-deck.pdf

@@ -5005,11 +5005,11 @@
     "computedY" : 121.269,
     "placementX" : 632.667,
     "placementY" : 121.269,
-    "placementWidth" : 281.289,
+    "placementWidth" : 266.879,
     "placementHeight" : 48.316,
     "startPage" : 1,
     "endPage" : 1,
-    "contentWidth" : 281.289,
+    "contentWidth" : 266.879,
     "contentHeight" : 48.316,
     "margin" : {
       "top" : 0.0,
@@ -5065,11 +5065,11 @@
     "computedY" : 132.269,
     "placementX" : 643.667,
     "placementY" : 132.269,
-    "placementWidth" : 259.289,
+    "placementWidth" : 244.879,
     "placementHeight" : 16.185,
     "startPage" : 1,
     "endPage" : 1,
-    "contentWidth" : 259.289,
+    "contentWidth" : 244.879,
     "contentHeight" : 16.185,
     "margin" : {
       "top" : 0.0,
@@ -6235,11 +6235,11 @@
     "computedY" : 225.886,
     "placementX" : 729.0,
     "placementY" : 225.886,
-    "placementWidth" : 45.95,
+    "placementWidth" : 39.016,
     "placementHeight" : 7.215,
     "startPage" : 2,
     "endPage" : 2,
-    "contentWidth" : 45.95,
+    "contentWidth" : 39.016,
     "contentHeight" : 7.215,
     "margin" : {
       "top" : 0.0,