VolmLib pin removal

- The build resolves VolmLib master-SNAPSHOT when no sibling checkout is substituted
- The native runtime manifest, roots and keep rules come from the embedded natives
- The packed jar natives are verified against the embedded provider shas
- Every jar carries META-INF/volmit/volmlib.properties
- The build logs the resolved VolmLib once
- publishedNativeRuntime, the loader coordinate flags, mavenLocal and publish-volmlib are gone

gradle/volmlib-stamp.gradle

@@ -0,0 +1,26 @@
+/*
+ * Iris is a World Generator for Minecraft Servers
+ * Copyright (c) 2026 Arcane Arts (Volmit Software)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+// Writes the VolmLib provenance that gradle/volmlib-resolution.settings.gradle resolved. Every shipped jar
+// carries it as META-INF/volmit/volmlib.properties.
+Map<String, String> volmLibStamp = (Map<String, String>) gradle.extensions.extraProperties.get('volmLibStamp')
+
+tasks.register('generateVolmLibStamp', WriteProperties) {
+    destinationFile.set(layout.buildDirectory.file('generated/volmlib-stamp/volmlib.properties'))
+    properties(volmLibStamp)
+}