Context

wt page -p <page_id> [-l <lsn>] <uri> dumps a disagg page chain. The base page goes through {}wti_debug_disk _and prints structured per-cell output. Each delta in the chain is dumped via }}{{_wt_log_data_dump as raw hex, so operators see a clean structured base followed by an opaque hex pile per delta.

Depends on WT-17341 (wt page subcommand).

Motivation

Two problems with the raw hex dump:

1. To get anything readable the operator has to feed the hex through the separate decode tool.
2. The raw hex exposes key and value bytes with no honouring of the -U / -K redaction flags, so a chain that contains user data is dumped in the clear even when the base page on the same invocation is redacted.

Definition of Done

1. Add {}wti_debug_disk_delta _in src/btree/bt_debug.c that iterates a delta WT_PAGE_HEADER using the existing WT_CELL_FOREACH_DELTA_LEAF / WT_CELL_FOREACH_DELTA_INT macros and prints per-cell structured output paralleling }}{{{}_wti_debug_disk.
2. Leaf deltas (WT_PAGE_ROW_LEAF): print key, delta_op (update / delete), value bytes, and time window. Honour -U / -K redaction flags.
3. Internal deltas (WT_PAGE_ROW_INT): print key and child cookie (page_id, base_lsn, size, checksum) via __wt_block_disagg_addr_unpack. A failed unpack reports inline and the dump continues.
4. Dispatch from {}wt_debug_disagg_page_id _for every chain result index > 0, threading results[0].data as the base header. Drop the existing }}{{_wt_log_data_dump call and the "structured delta decoding is not yet supported" warning.