Describe the bug

Pressing Enter in the desktop app composer has no effect — messages cannot be sent. Initially only new sessions were affected (historical sessions could send), but later all sessions stopped working.

To Reproduce

1. Open Hermes Desktop app (v0.15.1) on macOS
2. Type any message in the composer input
3. Press Enter
4. Nothing happens — no message sent, no error shown

Expected behavior

Pressing Enter should submit the message and start a conversation.

Environment

• Hermes Desktop: v0.15.1
• Backend/CLI: v0.16.0 (v2026.6.5)
• OS: macOS 15.6.1 (arm64)
• Model: DeepSeek V4 Pro (custom provider ds4)
• Display language: zh (Simplified Chinese)
• Gateway: running (launchd)

Diagnostics

• hermes doctor: DeepSeek API key OK (custom provider ds4 works — HTTP 200 confirmed)
• hermes status: gateway running, Feishu configured
• WebSocket: connected (gui.log shows ws accepted, messages flowing with parse_errors=0, dispatch_crashes=0, send_failures=0)
• Agent log: no session.create RPC calls registered — messages never reach the gateway
• hermes --tui CLI TUI works correctly as a workaround

Additional context

Desktop log shows multiple boot attempts with bootstrap failures (HTTP 404 from GitHub for install.sh) before eventually starting successfully using existing CLI. Desktop app was installed from the v0.16.0 git repo but the packaged Electron app is v0.15.1.