Complete minimum-order verification

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Summary

• add the complete order-12 census and all twelve shard logs
• establish that exactly two isomorphism classes are counterexamples of minimum order
• include the second witness and correct the through-order-11 census total
• strengthen the independent exact verifiers
• polish the arXiv source, including the exact census table and full witness data
• document the independent contemporaneous work of Matherne and Morales with neutral chronology
• correct the MathOverflow link and generalized-nets journal citation
• add public CI for all exact verifiers, archived checksums, and the census-program build

Why

The original minimum-order summary omitted orders 1 through 8 from one
claw-free subtotal and did not package the complete order-12 classification.
This branch makes the headline counts match the underlying shard logs and
keeps the hand-proved counterexample separate from the computational
minimality result.

Verification

• python3 verify.py
• python3 verify_claw_schur.py
• python3 verify_power_sum.py
• shasum -a 256 -c SHA256SUMS
• cc -O3 -std=c11 -Wall -Wextra -pedantic clawsweep.c
• three clean isolated pdflatex passes
• archive and source-hygiene checks
• visual inspection of all four rendered pages
• public exact-verification workflow