docs(examples): publish the PPTX twins in the showcase (#443)

* docs(examples): add PDF→PPTX twins for the business, financial, and master reports

The 2.1 PPTX backend shipped with one bespoke twin-output hero and the
Engine Deck PPTX. Add editable-PowerPoint twins for three real document
examples so the "one source, two formats" story spans everyday business
documents: BusinessReportPptxExample, FinancialReportPptxExample, and
MasterShowcasePptxExample each reuse their source example's composition and
emit the deck via buildPptx().

Extract a shared document(Path) session factory and a compose(DocumentSession)
method on BusinessReportExample and MasterShowcaseExample (FinancialReport
already had compose()), so the PDF generate() and the PPTX twin build from an
identical session config kept in one place. The report bodies are unchanged —
the large line counts on those two files are the method-extraction re-indent
(review with git diff -w).

FlagshipPptxTwinNativeShapeTest opens each rendered deck with Apache POI and
asserts native shapes dominate with only the genuinely un-vectorizable regions
rasterising (a clip-masked composite, a photo, two barcodes). The twins are
registered in GenerateAllExamples (exercised by the generate-every-example
smoke test) and linked from the examples gallery with committed .pptx previews.

* docs(examples): publish the PPTX twins in the showcase

The showcase could not surface a deck at all. ShowcaseSync selected artifacts
with endsWith(".pdf") and a manifest entry carried a single `pdf` field, so the
flagships that render both formats advertised only half their output — on the
release that makes PowerPoint output the headline.

Teach the sync to pick up a same-named .pptx sitting beside a PDF, publish it
under web/showcase/pptx/, and carry it as an optional `pptx` field. The card
gains a Get PPTX action only when the example actually rendered one, so the 82
PDF-only cards are untouched rather than carrying a dead link. The deck reuses
the PDF's thumbnail: both backends draw the same resolved layout, so a separate
render would be the same picture, and POI has no page rasterizer to make one.

Five flagships now ship both formats — business-report, engine-deck,
financial-report, master-showcase and twin-output, the last of which had no
showcase card at all until now. maven-banner renders a deck with no PDF sibling;
cards are PDF-driven and there is nothing to build its preview from, so it stays
out.

Fix a duplicate tag chip while regenerating: every entry passes its group as a
tag and withCategory prepends the same value, so 37 cards rendered the chip
twice. Deduplicating inside withCategory covers all of them and cannot be
reintroduced from a call site.

The three new twin examples came from a branch predating the removal of the
no-arg buildPptx(); they now name their destination like every other example.

Verified: full reactor clean verify green (1522 tests, 0 failures). Checked in
the running site — 5 of 87 cards carry the action, PDF-only cards show exactly
View PDF + View Code, the deck serves 200 with the OOXML content type and a PK
signature, no card renders a duplicate tag, and every manifest path resolves on
disk. Regeneration churn (every PDF re-renders with a fresh timestamp, 24 PNGs
re-encode) is deliberately left out; the release cut regenerates it wholesale.

Author: DemchaAV

assets/readme/examples/business-report.pptx

@@ -119,9 +119,9 @@ are with the canonical DSL, then jump to its detailed section below.
 | [Word export (DOCX)](#word-export-docx) | `DocxSemanticBackend` — the same session renders a fixed-layout PDF and an editable Word file; paragraphs / lists / tables / images map 1:1, charts fall back to their data table | [PDF](../assets/readme/examples/word-export-companion.pdf) · [DOCX](../assets/readme/examples/word-export-companion.docx) · [Source](src/main/java/com/demcha/examples/features/docx/WordExportExample.java) |
 | [Layout snapshot regression](#layout-snapshot-regression) | Deterministic `layoutSnapshot()` workflow with baseline + drift report — production regression-testing pattern | [PDF](../assets/readme/examples/invoice-snapshot-regression.pdf) · [Source](src/main/java/com/demcha/examples/features/snapshots/LayoutSnapshotRegressionExample.java) |
 | [Debug overlay](#debug-overlay) | `DocumentDebugOptions` — guide lines + semantic node-path labels on the sheet; trace any misplaced block back to the builder call that authored it | [PDF](../assets/readme/examples/debug-overlay.pdf) · [Source](src/main/java/com/demcha/examples/features/debug/DebugOverlayExample.java) |
-| [Business report cover](#business-report-cover) | Single-page Q1 investor brief — hero image, KPI cards, bar chart, metrics table | [PDF](../assets/readme/examples/business-report.pdf) · [Source](src/main/java/com/demcha/examples/flagships/BusinessReportExample.java) |
-| Financial report one-pager | Single-page monthly financial dashboard — three margin gauges, cash & stacked-OPEX charts, a revenue donut, and forecast bars; all v1.8 native vector charts plus inline sparklines and a path-clipped photo masthead | [PDF](../assets/readme/examples/financial-report.pdf) · [Source](src/main/java/com/demcha/examples/flagships/FinancialReportExample.java) |
-| [Master showcase](#master-showcase) | Kitchen-sink "Q2 sample report" combining the canonical surface end-to-end | [PDF](../assets/readme/examples/master-showcase.pdf) · [Source](src/main/java/com/demcha/examples/flagships/MasterShowcaseExample.java) |
+| [Business report cover](#business-report-cover) | Single-page Q1 investor brief — hero image, KPI cards, bar chart, metrics table; the same composition also renders as an editable PowerPoint deck (KPI cards, chart, and table stay native shapes) via `buildPptx()` | [PDF](../assets/readme/examples/business-report.pdf) · [PPTX](../assets/readme/examples/business-report.pptx) · [Source](src/main/java/com/demcha/examples/flagships/BusinessReportExample.java) · [PPTX source](src/main/java/com/demcha/examples/flagships/BusinessReportPptxExample.java) |
+| Financial report one-pager | Single-page monthly financial dashboard — three margin gauges, cash & stacked-OPEX charts, a revenue donut, and forecast bars; all v1.8 native vector charts plus inline sparklines and a path-clipped photo masthead; the same composition also renders as an editable PowerPoint deck via `buildPptx()` | [PDF](../assets/readme/examples/financial-report.pdf) · [PPTX](../assets/readme/examples/financial-report.pptx) · [Source](src/main/java/com/demcha/examples/flagships/FinancialReportExample.java) · [PPTX source](src/main/java/com/demcha/examples/flagships/FinancialReportPptxExample.java) |
+| [Master showcase](#master-showcase) | Kitchen-sink "Q2 sample report" combining the canonical surface end-to-end; the same composition also renders as a multi-slide editable PowerPoint deck via `buildPptx()` | [PDF](../assets/readme/examples/master-showcase.pdf) · [PPTX](../assets/readme/examples/master-showcase.pptx) · [Source](src/main/java/com/demcha/examples/flagships/MasterShowcaseExample.java) · [PPTX source](src/main/java/com/demcha/examples/flagships/MasterShowcasePptxExample.java) |
 | Feature catalog | Browsable reference PDF: every shipped capability as a block — outline-clickable heading, the exact API call, the rendered result right under it | [PDF](../assets/readme/examples/feature-catalog.pdf) · [Source](src/main/java/com/demcha/examples/flagships/FeatureCatalogExample.java) |
 | Book template | A full novel front: full-bleed wave cover, a clickable dotted-leader table of contents with live page numbers, and chapters — the v1.9 book primitives (`pageMargins`, `addTableOfContents`, `DocumentPageNumbering`, container `bookmark`, `viewerPreferences`) in **one session**, no external PDF merge | [PDF](../assets/readme/examples/book-template.pdf) · [Source](src/main/java/com/demcha/examples/features/title/BookTemplateExample.java) |
 
@@ -1104,8 +1104,12 @@ strategic-highlights bullet list paired with a five-quarter Revenue /
 Profit bar chart, YoY metrics table, and a confidential / page-number
 footer. Use this as the visual reference for landing-page hero shots.
 
+The same composition also emits an editable PowerPoint deck (`BusinessReportPptxExample` — one page, one slide; KPI cards, the native chart, and the metrics table stay editable shapes).
+
 [📄 View PDF](../assets/readme/examples/business-report.pdf) ·
-[📜 Full source](src/main/java/com/demcha/examples/flagships/BusinessReportExample.java)
+[🖥 View PPTX](../assets/readme/examples/business-report.pptx) ·
+[📜 Full source](src/main/java/com/demcha/examples/flagships/BusinessReportExample.java) ·
+[📜 PPTX twin](src/main/java/com/demcha/examples/flagships/BusinessReportPptxExample.java)
 
 ### Master showcase
 
@@ -1115,8 +1119,12 @@ shape container + branded QR + executive summary + zebra-striped
 totals table + accent-bordered highlight cards + Code 128 footer
 barcode. Reference it when composing your own multi-page documents.
 
+The same composition also emits an editable PowerPoint deck (`MasterShowcasePptxExample` — each page becomes one slide; rich text, the advanced table, and chrome stay native shapes, and only the rotated clip-masked seal and the barcodes rasterise).
+
 [📄 View PDF](../assets/readme/examples/master-showcase.pdf) ·
-[📜 Full source](src/main/java/com/demcha/examples/flagships/MasterShowcaseExample.java)
+[🖥 View PPTX](../assets/readme/examples/master-showcase.pptx) ·
+[📜 Full source](src/main/java/com/demcha/examples/flagships/MasterShowcaseExample.java) ·
+[📜 PPTX twin](src/main/java/com/demcha/examples/flagships/MasterShowcasePptxExample.java)
 
 ---
 

assets/readme/examples/financial-report.pptx

@@ -44,11 +44,14 @@
 import com.demcha.examples.features.title.PoetryTitlePageExample;
 import com.demcha.examples.features.transforms.TransformsExample;
 import com.demcha.examples.flagships.BusinessReportExample;
+import com.demcha.examples.flagships.BusinessReportPptxExample;
 import com.demcha.examples.flagships.EngineDeckExample;
 import com.demcha.examples.flagships.EngineDeckPptxExample;
 import com.demcha.examples.flagships.FeatureCatalogExample;
 import com.demcha.examples.flagships.FinancialReportExample;
+import com.demcha.examples.flagships.FinancialReportPptxExample;
 import com.demcha.examples.flagships.MasterShowcaseExample;
+import com.demcha.examples.flagships.MasterShowcasePptxExample;
 import com.demcha.examples.flagships.MavenBannerPptxExample;
 import com.demcha.examples.flagships.ModuleFirstFileExample;
 import com.demcha.examples.flagships.TwinOutputExample;
@@ -212,13 +215,16 @@ public static void main(String[] args) throws Exception {
         // === Flagships ===
         System.out.println("Generated: " + ModuleFirstFileExample.generate());
         System.out.println("Generated: " + MasterShowcaseExample.generate());
+        System.out.println("Generated: " + MasterShowcasePptxExample.generate());
         System.out.println("Generated: " + FeatureCatalogExample.generate());
         System.out.println("Generated: " + BusinessReportExample.generate());
+        System.out.println("Generated: " + BusinessReportPptxExample.generate());
         System.out.println("Generated: " + EngineDeckExample.generate());
         System.out.println("Generated: " + EngineDeckPptxExample.generate());
         System.out.println("Generated: " + MavenBannerPptxExample.generate());
         System.out.println("Generated: " + TwinOutputExample.generate());
         System.out.println("Generated: " + FinancialReportExample.generate());
+        System.out.println("Generated: " + FinancialReportPptxExample.generate());
         System.out.println("Generated: " + BookTemplateExample.generate());
         System.out.println("Generated: " + PoetryTitlePageExample.generate());
     }