Build offline OpenPrestige release bundles

Rename the injector and package it with an embedded payload for Windows, Linux, and macOS x64/ARM64. Add a core-only ImGui native build, multi-platform CI and release packaging, and shared per-user storage with legacy config migration.

scripts/test_release.py

@@ -0,0 +1,48 @@
+"""Check this repository's release contents and architecture requirements."""
+import contextlib
+import hashlib
+import io
+from pathlib import Path
+import tempfile
+import unittest
+import zipfile
+
+import package_release
+
+
+class ReleasePackaging(unittest.TestCase):
+    def test_contents_and_checksums(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            injector = root / "injector.exe"
+            library = root / "prestige_native.dll"
+            jar = root / "prestige-1.2.3.jar"
+            injector.write_bytes(b"launcher")
+            library.write_bytes(b"library")
+            with zipfile.ZipFile(jar, "w") as payload:
+                payload.writestr("example.class", b"payload")
+            out = root / "release"
+            with contextlib.redirect_stdout(io.StringIO()):
+                package_release.make_zip(str(out), "1.2.3", "windows-x86_64", str(injector), str(library), str(jar))
+            archive = next(out.glob("*.zip"))
+            with zipfile.ZipFile(archive) as bundle:
+                names = {Path(name).name for name in bundle.namelist()}
+                self.assertEqual(names, {"OpenPrestigeInjector.exe", library.name, "README.txt"})
+                readme = bundle.read("openprestige-1.2.3-windows-x86_64/README.txt").decode()
+                self.assertIn("embeds its payload", readme)
+                self.assertNotIn("Keep the payload JAR beside", readme)
+            package_release.checksums(str(out))
+            expected = f"{hashlib.sha256(archive.read_bytes()).hexdigest()}  {archive.name}\n"
+            self.assertEqual((out / "SHA256SUMS.txt").read_text(), expected)
+
+    def test_arm_native_required(self):
+        with tempfile.TemporaryDirectory() as directory:
+            jar = Path(directory) / "prestige-1.2.3.jar"
+            with zipfile.ZipFile(jar, "w"):
+                pass
+            with self.assertRaisesRegex(ValueError, "ARM64 payload is missing"):
+                package_release.make_zip(directory, "1.2.3", "windows-aarch64", "unused.exe", "unused.dll", str(jar))
+
+
+if __name__ == "__main__":
+    unittest.main()