Move CEIL macro to basic.h and remove unnecessary heartbeat reset

- Move the CEIL macro from config.h to basic.h alongside MIN/MAX, and
  use it in deadline_to_timeout for the rounding-up division
- Remove the heartbeat reset in complete_view_change_and_become_primary
  since it was not needed — heartbeat is already set when the node
  enters STATUS_CHANGE_VIEW, which is close enough in time

https://claude.ai/code/session_0184gHjra7fsmSPZ4kppaGhC

src/server.c

@@ -517,7 +517,6 @@ complete_view_change_and_become_primary(ServerState *state)
     broadcast_to_peers_ex(state, &begin_view_message.base, state->log.entries, state->log.count * sizeof(LogEntry));
 
     clear_view_change_fields(state);
-    state->heartbeat = state->now;
     return HR_OK;
 }