tpcds_dsdgen.h: include real tpcds headers instead of re-declaring structs

The old approach manually copied all struct definitions (W_STORE_SALES_TBL,
ds_addr_t, etc.) into tpcds_dsdgen.h, which could silently diverge from the
actual generator sources — as demonstrated by the missing ds_addr_t.plus4
field that caused stack smashing in call_center/warehouse/customer_address.

New approach: include the canonical tpcds w_*.h headers directly.  All 24
table structs are now sourced from the real implementation files.  The
TPCDS_* integer constants are kept as prefixed literals (tables.h defines
bare macros like CALL_CENTER=0 that would collide with C++ enum member names).

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

Author: tsafin