feat: bootstrap secure cross-platform assistant

Establish the Electron foundation and pluggable agent runtime so desktop workflows can evolve safely across supported platforms.

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

src/shared/ipc-channels.ts

@@ -0,0 +1,10 @@
+export const ipcChannels = {
+  appInfo: 'app:get-info',
+  appShow: 'app:show',
+  appHide: 'app:hide',
+  conversationNew: 'conversation:new',
+  agentStatus: 'agent:get-status',
+  agentRun: 'agent:run',
+  agentCancel: 'agent:cancel',
+  agentEvent: 'agent:event'
+} as const