Add exact Q26 queen-domination attack

[jkolantree]

Summary

• add an independently reconstructed exact attack package for the unresolved 13-versus-14 queen-domination decision on a 26×26 board
• add direct CNF, line-incidence CNF, and direct OPB encoding lanes
• add two independent finite witness checkers, deterministic Hilbert/D4 reductions, and explicitly scoped Weakley-derived discovery constraints
• retain and independently verify the public 14-queen upper-bound witness
• classify every bounded Q26 search run as UNKNOWN; this PR does not claim a 13-queen witness or an impossibility proof

Evidence boundary

The mathematical status remains 13 ≤ γ(Q26) ≤ 14. Positive promotion requires a 13-coordinate witness that passes both 676-square checkers. Negative promotion requires a frozen formula, retained proof, independent proof replay, and a checked encoding bridge. The theorem-strengthened mode is a discovery accelerator, not automatic publication authority.

No claim or fixture identifier, paper, PDF, release, tag, DOI, Zenodo record, roadmap ordering, workflow, ruleset, or setting is changed.

Verification

• python -m unittest tests.test_q26_queen_domination -v — 20 passed
• python tools/verify_inventory_contexts.py — PASS; identical 118-file checkout, linked-worktree, and archive inventories
• python tools/verify_manifest.py — PASS; 118 files
• python tools/check_markdown_math.py — PASS
• F08, F10, F11, F12, and F13 fixture checkers — PASS
• python -m unittest discover -s tests -v — 256 passed, 1 skipped because Windows symlink creation privilege was unavailable
• git diff --check and final clean-worktree check — PASS
• PDF build — not run; latexmk is unavailable