fix(plugins): handle reinstall cleanly in installPlugin handler

Previously, reinstalling an already-installed plugin would start a
second process without stopping the first one (duplicate processes
sharing the same UUID key in pluginProcesses Map, old process leaked).

Now the handler stops and removes the existing plugin entry before
copying the new files, so reinstalling cleanly replaces the running
process. Also adds force:true to cp so files are always overwritten.

Author: tech-stack-studios

electron/main.cjs

@@ -544,9 +544,12 @@ function registerIpcHandlers() {
       return { ok: false, error: 'Invalid manifest: missing UUID or Actions array' }
     }
     const destDir = path.join(getPluginsDir(), `${manifest.UUID}.sdPlugin`)
+    // Stop and remove any existing installation with the same UUID (handles reinstall)
+    stopPlugin(manifest.UUID)
+    pluginManifests = pluginManifests.filter(p => p.manifest.UUID !== manifest.UUID)
     try {
       await fs.promises.mkdir(getPluginsDir(), { recursive: true })
-      await fs.promises.cp(resolved, destDir, { recursive: true })
+      await fs.promises.cp(resolved, destDir, { recursive: true, force: true })
     } catch (err) {
       return { ok: false, error: err.message }
     }