Sync Decorator to Java 25: H6 file labels, fix Main.java JDK-output mismatch, README mapping

02-structural/decorator/README.md

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+# Decorator Design Pattern — Java Example
+
+**Pattern:** Structural → Decorator
+**Article:** https://ankurm.com/decorator-design-pattern-java/
+
+## What this example shows
+
+Builds a text-processing pipeline where behaviours (trim, uppercase, profanity filter) are stacked as wrapper objects around a `PlainTextProcessor`, all sharing the `TextProcessor` interface — the same idea behind `new BufferedReader(new InputStreamReader(...))` in the JDK.
+
+## How to run
+
+```bash
+javac decorator/*.java -d out/decorator
+java -cp out/decorator decorator.Main
+```
+
+Requires Java 25.
+
+## Post Section ↔ File Mapping
+
+| Post Section | File(s) |
+|---|---|
+| Step 1 — Component Interface | `TextProcessor.java` |
+| Step 2 — Concrete Component | `PlainTextProcessor.java` |
+| Step 3 — Base Decorator | `TextDecorator.java` |
+| Step 4 — Concrete Decorators | `UpperCaseDecorator.java`, `TrimDecorator.java`, `ProfanityFilterDecorator.java` |
+| Stacking the Decorators — Order Matters | `Main.java` |
+
+Note: the JDK `InputStream`/`BufferedInputStream`/`GZIPInputStream` snippet under "Decorator in the JDK: I/O Streams" is illustrative only — it is not part of this repository's runnable example.
+
+Article: https://ankurm.com/decorator-design-pattern-java/
+All patterns: https://ankurm.com/design-patterns-java/