Fix extract_doe_region.py SLOT_FMT drift; regenerate report with real data

FABRIC-3.md §XXXV.15. §XXXV.12 added an explicit _align_pad field to
doe_trial_slot_t to fix a struct-alignment bug, but never updated the
Python extractor's SLOT_FMT/SLOT_CRC_SPAN to match -- every field after
isa was read from the wrong byte offset, so slot_crc read wrong bytes
entirely and every legitimate record (including the real, live
campaign's own first two clean trials) was flagged as CRC-corrupt.
Fixed; SLOT_SIZE assertion tightened from <= to == to catch this drift
immediately next time.

Regenerated multiuser_doe_report.pdf against the real campaign's actual
first two trials: run=0 (cfg=0, nw=2, uniform, fail=0) and run=1 (cfg=5,
nw=8, heterogeneous, fail=0), both fleet_conserved=1 at exactly Q48.16
1.0. Real report, real data, first time this has happened for this
campaign. disk/artemis.img itself and the live campaign's log directory
are deliberately left uncommitted -- still being written by the running
campaign.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BWpNjdwPtFLuVLaAq44L9K

scripts/extract_doe_region.py

@@ -73,11 +73,13 @@ CTRL_CRC_SPAN = struct.calcsize("<QIIII")  # everything before hdr_crc
 
 # doe_trial_slot_t: fleet_k_q48(u64) switch_count_cumulative(u64)
 # run_id(u32) cfg(u32) rep(u32) nw(u32) mode(u32) fail_count(u32)
-# fleet_conserved(u32) isa(8s) slot_crc(u64), rest is padding to 64.
-SLOT_FMT = "<QQIIIIIII8sQ"
+# fleet_conserved(u32) isa(8s) _align_pad(u32, explicit -- see
+# doe_region.h's own comment on why: brings slot_crc to an 8-aligned
+# offset without relying on implicit compiler padding) slot_crc(u64).
+SLOT_FMT = "<QQIIIIIII8sIQ"
 SLOT_SIZE = struct.calcsize(SLOT_FMT)
-SLOT_CRC_SPAN = struct.calcsize("<QQIIIIIII8s")  # everything before slot_crc
-assert SLOT_SIZE <= DOE_SLOT_SIZE
+SLOT_CRC_SPAN = struct.calcsize("<QQIIIIIII8sI")  # everything before slot_crc
+assert SLOT_SIZE == DOE_SLOT_SIZE
 
 
 # CRC-64/XZ, same polynomial/algorithm as compute_crc64() in
@@ -186,7 +188,7 @@ def read_ring(dev_path: str):
             f.seek(blk_off + slot_off_in_devblock)
             raw = f.read(SLOT_SIZE)
             (fleet_k_q48, switch_count, run_id, cfg, rep, nw, mode,
-             fail_count, fleet_conserved, isa_raw, slot_crc) = struct.unpack(SLOT_FMT, raw)
+             fail_count, fleet_conserved, isa_raw, _align_pad, slot_crc) = struct.unpack(SLOT_FMT, raw)
 
             want_slot_crc = compute_crc64(raw[:SLOT_CRC_SPAN])
             if want_slot_crc != slot_crc: