Port to Paper 26.2 (2.0.0)

Snapshot of the 26.2 port published on Modrinth as 2.0.0 on 2026-08-06.
Built against paper-api 26.2.build.100-stable on Java 25. The changes had
only lived in the working tree on HPDebian (/root/mc-26.2/repos); this
commit records them as they were shipped. Details are in the 2.0.0 section
of the Modrinth changelog.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

pom.xml

@@ -13,10 +13,10 @@
     <description>A comprehensive player-to-player marketplace plugin with sales, auctions, and negotiations</description>
 
     <properties>
-        <maven.compiler.source>21</maven.compiler.source>
-        <maven.compiler.target>21</maven.compiler.target>
+        <maven.compiler.source>25</maven.compiler.source>
+        <maven.compiler.target>25</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <paper.version>1.21.1-R0.1-SNAPSHOT</paper.version>
+        <paper.version>26.2.build.100-stable</paper.version>
     </properties>
 
     <repositories>
@@ -37,7 +37,7 @@
         <dependency>
             <groupId>io.papermc.paper</groupId>
             <artifactId>paper-api</artifactId>
-            <version>${paper.version}</version>
+            <version>26.2.build.100-stable</version>
             <scope>provided</scope>
         </dependency>
 
@@ -72,15 +72,15 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.12.1</version>
                 <configuration>
-                    <source>21</source>
-                    <target>21</target>
+                    <source>25</source>
+                    <target>25</target>
                 </configuration>
             </plugin>
 
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-shade-plugin</artifactId>
-                <version>3.5.1</version>
+                <version>3.6.2</version>
                 <executions>
                     <execution>
                         <phase>package</phase>