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

experiments/bare_metal/analysis/tables/multiuser_cell_summary.csv

@@ -0,0 +1,3 @@
+"nw","mode","n_trials","n_fail","fail_rate","mean_fail_count","mean_fleet_k","pct_conserved","mean_switch_cnt"
+"2","uniform",1,0,0,0,1,1,0
+"8","heterogeneous",1,0,0,0,1,1,0