feat: add maximize window support with MRU focus tracking and demo timing configs

Implement client maximize/unmaximize toggle and state tracking via CLIENT_MAXIMIZED flag, add MRU (most-recently-used) doubly-linked list per workspace for intelligent focus restoration on client unmanage, introduce configurable focus-follow delay (0-1000ms) for sloppy focus mode, and add demo mode timing parameters (step_delay, ai_timeout, window_timeout) with corresponding wait condition enum and configuration parsing in the [demo] section.

build/client.d

@@ -18,7 +18,7 @@ build/client.o: src/client.c include/client.h include/dwn.h \
  /usr/include/dbus-1.0/dbus/dbus-server.h \
  /usr/include/dbus-1.0/dbus/dbus-signature.h \
  /usr/include/dbus-1.0/dbus/dbus-syntax.h \
- /usr/include/dbus-1.0/dbus/dbus-threads.h
+ /usr/include/dbus-1.0/dbus/dbus-threads.h include/layout.h
 include/client.h:
 include/dwn.h:
 include/atoms.h:
@@ -45,3 +45,4 @@ include/notifications.h:
 /usr/include/dbus-1.0/dbus/dbus-signature.h:
 /usr/include/dbus-1.0/dbus/dbus-syntax.h:
 /usr/include/dbus-1.0/dbus/dbus-threads.h:
+include/layout.h: