build: add BOM module

Publishable artifact io.github.dfa1.vortex:bom that users import
in <dependencyManagement> to get consistent versions across all
vortex-java modules (core, reader, writer, csv, parquet).

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

Author: dfa1

TODO.md

@@ -62,7 +62,6 @@ Remaining 0.3 MB gap — biggest to smallest:
   boundaries. Keep `integration`, `performance`, and `cli` as separate modules. Package structure
   (`encoding`, `io`, `writer`) already enforces internal boundaries without Maven.
 - [ ] prefix all modules with "vortex-"
-- [ ] add BOM module
 - [ ] deploy to maven central
 - [ ] switch back to module-path, but keep in mind these 2 blockers
 

bom/pom.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>io.github.dfa1.vortex</groupId>
+		<artifactId>vortex-java</artifactId>
+		<version>0.1.0-SNAPSHOT</version>
+	</parent>
+
+	<artifactId>bom</artifactId>
+	<packaging>pom</packaging>
+
+	<name>vortex-java-bom</name>
+	<description>Bill of Materials for vortex-java. Import this POM in dependencyManagement to get consistent versions of all vortex-java modules.</description>
+
+	<dependencyManagement>
+		<dependencies>
+			<dependency>
+				<groupId>io.github.dfa1.vortex</groupId>
+				<artifactId>core</artifactId>
+				<version>${project.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>io.github.dfa1.vortex</groupId>
+				<artifactId>reader</artifactId>
+				<version>${project.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>io.github.dfa1.vortex</groupId>
+				<artifactId>writer</artifactId>
+				<version>${project.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>io.github.dfa1.vortex</groupId>
+				<artifactId>csv</artifactId>
+				<version>${project.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>io.github.dfa1.vortex</groupId>
+				<artifactId>parquet</artifactId>
+				<version>${project.version}</version>
+			</dependency>
+		</dependencies>
+	</dependencyManagement>
+</project>

pom.xml

@@ -43,6 +43,7 @@
 		<module>writer</module>
 		<module>csv</module>
 		<module>parquet</module>
+		<module>bom</module>
 		<module>cli</module>
 		<module>integration</module>
 		<module>performance</module>