feat: SQLite persistence, default /core commands, Bukkit events, bootstrap

CRCore bootstrap class: one-line setup for game plugins (new CRCore(this).enable()).
Wires SQLite, services with event firing, and the /core command tree.

SQLite layer (fr.luc.crcore.database): Database wrapper exposing execute/update/
queryOne/query plus a fluent TableBuilder. ColumnType enum, RowMapper interface,
DatabaseException. Game plugins create their own tables in 2 lines via
db.table("foo").ifNotExists().column(...).create().

Repositories: SqliteTeamRepository and SqlitePlayerProfileRepository extend their
InMemory counterparts (write-through cache). 5 internal tables prefixed crcore_.

Command framework refactored for nested sub-commands: subcommand storage moved
from BaseCommand to AbstractCommand, recursive dispatch() and tabComplete(),
replaceSubCommand() for plugin overrides.

Default /core team commands (13 leaf sub-commands): create, delete, add, remove,
join, leave, info, list, transfer, visibility, score, top, setspawn. Each in its
own class under fr.luc.crcore.command.builtin.team, fully substitutable.

Bukkit events: 9 team events (Create/Dissolve/MemberAdd/MemberRemove/PlayerJoin/
LeadershipTransfer/VisibilityChange/ScoreChange/SpawnPointChange) + 3 player
events (ProfileCreate/Delete/ScoreChange). All post-only, non-cancellable.
BukkitEventFiringTeamServiceImpl and BukkitEventFiringPlayerProfileServiceImpl
override the on* hooks to call Bukkit.getPluginManager().callEvent.

JavaDoc on all new public classes and key existing ones. docs/, GEMINI.md and
PUML diagrams synced: new sections (built-in commands, events, database,
bootstrap), 4 new diagrams (builtin-commands, events, database, bootstrap-
sequence), and 7 new architecture decisions logged.

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

docs/diagrams/database-diagram.puml

@@ -0,0 +1,86 @@
+@startuml database-diagram
+title CR-Core — Database (SQLite wrapper)
+
+skinparam classAttributeIconSize 0
+hide empty members
+
+package "fr.luc.crcore.database" {
+
+  class Database {
+    - connection: Connection
+    + Database(file: File)
+    + execute(sql, params...): void
+    + update(sql, params...): int
+    + queryOne(sql, mapper, params...): Optional<T>
+    + query(sql, mapper, params...): List<T>
+    + inTransaction(block: Runnable): void
+    + table(name: String): TableBuilder
+    + tableExists(name: String): boolean
+    + getConnection(): Connection
+    + close(): void
+  }
+  Database ..|> "java.lang.AutoCloseable"
+
+  class TableBuilder {
+    - database: Database
+    - name: String
+    - columns: List<ColumnDef>
+    - ifNotExists: boolean
+    + ifNotExists(): TableBuilder
+    + column(name, type): ColumnDef
+    + create(): void
+  }
+
+  class "TableBuilder.ColumnDef" as ColumnDef {
+    - name: String
+    - type: ColumnType
+    - primaryKey: boolean
+    - notNull: boolean
+    - unique: boolean
+    - defaultValue: String
+    + primaryKey(): ColumnDef
+    + notNull(): ColumnDef
+    + unique(): ColumnDef
+    + defaultValue(expr: String): ColumnDef
+    + column(name, type): ColumnDef
+    + create(): void
+  }
+
+  enum ColumnType {
+    INTEGER
+    REAL
+    TEXT
+    BLOB
+    BOOLEAN
+    UUID
+    --
+    + getSqlType(): String
+  }
+
+  interface "RowMapper<T>" as RowMapper {
+    + map(rs: ResultSet): T
+  }
+
+  class DatabaseException
+  DatabaseException --|> RuntimeException
+
+  Database "1" *-- "*" TableBuilder : creates
+  TableBuilder "1" *-- "*" ColumnDef : contains
+  ColumnDef --> ColumnType : type
+  Database ..> RowMapper : uses
+  Database ..> DatabaseException : throws
+}
+
+note right of Database
+  Repositories SQLite de CR-Core
+  (SqliteTeamRepository,
+   SqlitePlayerProfileRepository)
+  utilisent Database pour
+  persister state team/player.
+
+  Les plugins de jeu utilisent
+  Database.table(...) pour
+  créer leurs tables custom.
+end note
+
+@enduml