fix(runtime): prevent dlclose() to avoid SIGSEGV on runtime teardown

Wrap LoadedRuntime._library in ManuallyDrop so dlclose() is never called.
dlclose() unmaps the library code; thread-local destructors inside liblua.so
then SIGSEGV when they try to run against the unmapped addresses.

Also filter out non-.lua plugins in the Lua runtime's discover_plugins()
so liblua.so does not attempt to load Rune plugins.

crates/owlry-core/src/plugins/runtime_loader.rs

@@ -10,6 +10,7 @@
 //! Note: This module is infrastructure for the runtime architecture. Full integration
 //! is pending Phase 5 (AUR Packaging) when runtime packages will be available.
 
+use std::mem::ManuallyDrop;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
@@ -69,8 +70,11 @@ pub struct ScriptRuntimeVTable {
 pub struct LoadedRuntime {
     /// Runtime name (for logging)
     name: &'static str,
-    /// Keep library alive
-    _library: Arc<Library>,
+    /// Keep library alive — wrapped in ManuallyDrop so we never call dlclose().
+    /// dlclose() unmaps the library code; any thread-local destructors inside the
+    /// library then SIGSEGV when they try to run against the unmapped addresses.
+    /// Runtime libraries live for the process lifetime, so leaking the handle is safe.
+    _library: ManuallyDrop<Arc<Library>>,
     /// Runtime vtable
     vtable: &'static ScriptRuntimeVTable,
     /// Runtime handle (state)
@@ -138,7 +142,7 @@ impl LoadedRuntime {
 
         Ok(Self {
             name,
-            _library: library,
+            _library: ManuallyDrop::new(library),
             vtable,
             handle,
             providers,
@@ -166,6 +170,8 @@ impl LoadedRuntime {
 impl Drop for LoadedRuntime {
     fn drop(&mut self) {
         (self.vtable.drop)(self.handle);
+        // Do NOT drop _library: ManuallyDrop ensures dlclose() is never called.
+        // See field comment for rationale.
     }
 }
 

crates/owlry-lua/src/loader.rs

@@ -186,6 +186,10 @@ pub fn discover_plugins(
 
         match PluginManifest::load(&manifest_path) {
             Ok(manifest) => {
+                // Skip plugins whose entry point is not a Lua file
+                if !manifest.plugin.entry.ends_with(".lua") {
+                    continue;
+                }
                 let id = manifest.plugin.id.clone();
                 if plugins.contains_key(&id) {
                     eprintln!(