fix: pass env to SDK subprocess and hide server Dock icon

1. Explicitly pass process.env to the Claude Agent SDK's env option,
   ensuring user shell env vars (ANTHROPIC_AUTH_TOKEN, ANTHROPIC_BASE_URL,
   etc.) reach the claude subprocess in packaged builds.
2. Spawn the standalone server via /bin/sh with exec to prevent the
   Electron binary from appearing as a separate Dock icon on macOS.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/lib/claude-client.ts

@@ -137,6 +137,10 @@ export function streamClaude(options: ClaudeStreamOptions): ReadableStream<strin
           abortController,
           includePartialMessages: true,
           permissionMode: (permissionMode as Options['permissionMode']) || 'acceptEdits',
+          // Explicitly pass the full process.env to the Claude Code subprocess.
+          // In packaged Electron, this includes user shell env vars (API keys, etc.)
+          // loaded by the main process via loadUserShellEnv().
+          env: process.env as Record<string, string>,
         };
 
         // Find claude binary for packaged app where PATH is limited