v0.3.15 — API key validation on connect

Changes

API key validation

• Add connection dialog now validates the API key before saving — calls GET /health to verify
• API Key update dialog also validates before saving
• Shows specific error banners:
  • "Server requires an API key" — when key is empty
  • "Invalid API key. Server returned 401." — when key is wrong
  • "Cannot reach host:port" — when server is unreachable
• Loading spinner while validating, buttons disabled during check
• Dialog stays open on failure so you can retry without re-entering all fields

From v0.3.14

• Updated README for Gateway API Server architecture
• server-patches/0001-tcp-nodelay-sse.patch for real-time SSE streaming
• Scroll to bottom after loading message history