chore: Add Maven wrapper and CI tooling

Add mvnw / .mvn so contributors and CI can build with a pinned Maven
version without a system install. Exclude the wrapper scripts from
pre-commit formatting. Refactor commit.yaml to share checkout/setup
steps via YAML anchors and grant the release job contents: write so
conventional-release can create the GitHub release and tag.

Author: thced

.github/workflows/commit.yaml

@@ -1,15 +1,21 @@
 name: Commit
 on: push
 
+permissions:
+  contents: read
+  id-token: read
+
 jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - &checkout
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
-      - uses: actions/setup-java@v5
+      - &setup-java
+        uses: actions/setup-java@v5
         with:
           distribution: 'temurin'
           java-version-file: .java-version
@@ -32,18 +38,13 @@ jobs:
   release:
     if: github.ref == 'refs/heads/master'
     runs-on: ubuntu-latest
-    needs:
-      - test
+    needs: test
+    permissions:
+      contents: write
+      id-token: write
     steps:
-      - uses: actions/checkout@v6
-        with:
-          fetch-depth: 0
-
-      - uses: actions/setup-java@v5
-        with:
-          distribution: 'temurin'
-          java-version-file: .java-version
-          cache: 'maven'
+      - *checkout
+      - *setup-java
 
       - name: Create release
         uses: extenda/actions/conventional-release@v0

.mvn/extensions.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<extensions>
+  <extension>
+    <groupId>com.google.cloud.artifactregistry</groupId>
+    <artifactId>artifactregistry-maven-wagon</artifactId>
+    <version>2.2.5</version>
+  </extension>
+</extensions>

.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,3 @@
+wrapperVersion=3.3.4
+distributionType=only-script
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.9.16/apache-maven-3.9.16-bin.zip

.pre-commit-config.yaml

@@ -1,4 +1,5 @@
 default_stages: [pre-commit]
+exclude: ^mvnw.*$
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v6.0.0