feat: initial CR-Core library (team + player + command framework)

Pure Maven library for CR Minecraft game plugins, targeting Paper 1.16.5.

Common abstractions (fr.luc.crcore.common): Identifiable, Named, ScoreHolder,
AbstractEntity, Repository<T>.

Team domain (fr.luc.crcore.team): Team entity with name/tag/color/leader/
visibility (PUBLIC|PRIVATE)/members/scores/spawn point, TeamMember,
TeamRole/TeamColor/TeamVisibility enums, TeamRanking record, TeamService with
overridable hooks (factories, validations, lifecycle events), in-memory
repository, dedicated exception hierarchy.

Player domain (fr.luc.crcore.player): PlayerProfile with named scores per
player, PlayerProfileService with auto-creation, individual rankings,
exception hierarchy. Both Team and PlayerProfile implement ScoreHolder.

Command framework (fr.luc.crcore.command): Command interface,
AbstractCommand base, BaseCommand (CommandExecutor + TabCompleter), SubCommand,
CommandContext, CommandResult, ArgumentType<T> + ArgumentTypes catalogue
(STRING, INTEGER, DOUBLE, BOOLEAN, ONLINE_PLAYER, enumOf, choice).

Docs (docs/) is the single source of truth: README, setup, features,
decisions log, and 6 PlantUML diagrams (team class/sequence/activity/join,
player class, command class).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

pom.xml

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>fr.luc</groupId>
+    <artifactId>CR-Core</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>CR-Core</name>
+    <description>Reusable core library for CR Minecraft game plugins (teams, commands, common abstractions).</description>
+
+    <properties>
+        <maven.compiler.source>16</maven.compiler.source>
+        <maven.compiler.target>16</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <repositories>
+        <repository>
+            <id>papermc</id>
+            <url>https://repo.papermc.io/repository/maven-public/</url>
+        </repository>
+        <repository>
+            <id>spigot-repo</id>
+            <url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
+        </repository>
+        <repository>
+            <id>sonatype</id>
+            <url>https://oss.sonatype.org/content/groups/public/</url>
+        </repository>
+    </repositories>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.destroystokyo.paper</groupId>
+            <artifactId>paper-api</artifactId>
+            <version>1.16.5-R0.1-SNAPSHOT</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>${project.artifactId}-${project.version}</finalName>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <source>${maven.compiler.source}</source>
+                    <target>${maven.compiler.target}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>