Add configuration option to disable dbus-daemon spawning

Problem

On unsupported platforms like OpenBSD, each claude invocation spawns a new dbus-daemon process that is never cleaned up on exit. This leads to accumulation of orphaned processes:

# pgrep -x dbus-daemon | wc -l
      22

There is currently no way to prevent this behavior.

Request

Add a configuration option (settings.json key or environment variable, e.g. DISABLE_DBUS=1) to disable dbus usage entirely, similar to existing options:

• USE_BUILTIN_RIPGREP=0 — use system ripgrep instead of built-in
• DISABLE_AUTOUPDATER=1 — disable auto-updates

Context

• Platform: OpenBSD 7.9
• Claude Code installed via npm
• dbus-daemon processes are orphaned on each claude exit and never cleaned up
• Setting DBUS_SESSION_BUS_ADDRESS may or may not help depending on whether dbus is spawned via libdbus autolaunch or directly as a subprocess