feat(releaser): release v1.5.0 — Node.js, multi-module Maven, configurable bump rules

- Add internal/node package: reads/writes package.json version (single or
  multi-path via node.package_json / node.package_jsons)
- Add maven.pom_paths support: update multiple pom.xml files in one release
  commit; pom_paths overrides pom_path; --pom flag clears pom_paths
- Add git.bump_rules config: per-type control of which version component bumps
  (breaking/feat/fix accept "patch" or "minor"); wired through version.Next()
  as a new sixth parameter
- Extract injectable function vars (absPath, gitAllCommits, gitCommitsSince,
  gitCommitFiles) to enable error-path testing without interfaces
- Achieve 100% per-package statement coverage across all 12 packages

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/commits/commits_test.go

@@ -83,6 +83,14 @@ func TestReleasableSet(t *testing.T) {
 	if !only[TypeFix] || only[TypeFeat] || only[TypeBreaking] {
 		t.Errorf("fix-only set: %v", only)
 	}
+	onlyFeat := ReleasableSet([]string{"feat"})
+	if onlyFeat[TypeFix] || !onlyFeat[TypeFeat] || onlyFeat[TypeBreaking] {
+		t.Errorf("feat-only set: %v", onlyFeat)
+	}
+	onlyBreaking := ReleasableSet([]string{"breaking"})
+	if onlyBreaking[TypeFix] || onlyBreaking[TypeFeat] || !onlyBreaking[TypeBreaking] {
+		t.Errorf("breaking-only set: %v", onlyBreaking)
+	}
 }
 
 func TestTypeString(t *testing.T) {