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.

injector/crates/loader/src/worker.rs

@@ -29,6 +29,7 @@ pub fn run() {
 }
 
 unsafe fn install() -> Result<(), String> {
+    crate::paths::initialize().map_err(|error| format!("create OpenPrestige data directory: {error}"))?;
     let vm = find_vm()?;
     let env = attach_current_thread(vm)?;
     struct Detach(VmPtr);
@@ -45,7 +46,7 @@ unsafe fn install() -> Result<(), String> {
     log!("JVMTI ready");
 
     let jar = write_payload()?;
-    log!("payload written to {}", jar.display());
+    log!("using payload at {}", jar.display());
 
     let loader = add_to_knot(&jni, &jar)?;
     log!("payload appended to the game class loader: {}", describe(&jni, loader));
@@ -103,7 +104,8 @@ unsafe fn find_vm() -> Result<VmPtr, String> {
 }
 
 fn write_payload() -> Result<PathBuf, String> {
-    let dir = std::env::temp_dir().join("PrestigeLoader");
+    let dir = crate::paths::initialize().map_err(|e| format!("create OpenPrestige data directory: {e}"))?
+        .join("runtime").join("payloads");
     std::fs::create_dir_all(&dir).map_err(|e| format!("create {}: {e}", dir.display()))?;
     let path = dir.join(format!("prestige-payload-{}.jar", std::process::id()));
     std::fs::write(&path, PAYLOAD).map_err(|e| format!("write {}: {e}", path.display()))?;