Review: add IRS Refund Tracker mirror and deterministic verifiers

[reacher-z]

Reviewer contribution

This completes a Track B review of #37 while preserving XuanRui LI's original commit and authorship. The original environment is retained in commit 63e61e9; the reviewer grading work is isolated in ee8972a.

What changed

• rebased the IRS Refund Tracker mirror onto current main, retaining Merriam-Webster and assigning IRS the non-conflicting port 40016
• synchronized the 17-site registry, Docker exposure, startup health counts, and port documentation
• added deterministic verifiers and judge rubrics for all 18 tasks
• required task-specific navigation so correct answers supplied from prior knowledge cannot pass
• added SQLite seed/live-state verification for David Kim's profile-update task
• supplied exact seeded credentials in every standalone authenticated task
• kept ground truth inside verifier code; tasks.jsonl contains no answer key

Verification

• python3 -m unittest discover -s sites/irs_refund/verify -p 'test_*.py' -v: 9 test groups pass
• positive, no-op, wrong-answer, and prior-knowledge cases cover all 18 tasks
• all 18 verifier wrappers pass their positive fixture and reject their no-op fixture
• each of the three visible identity-checklist answers is accepted
• task 8 rejects a correct self-report without the exact DB transition; the real browser-driven transition from (Seattle, Mail) to (Spokane, Email) passes
• py_compile, JSONL parsing, shell syntax, git diff --check, and asset checks pass
• final 5.92 GB Docker image builds; verifier files compile inside the image; 17/17 sites return HTTP 200
• IRS reset is byte-identical at SHA-256 c422556eef1a7cc3a761a600bd2b9058f4489c0375d49efa5744d9cd6ff3b9f5; parallel reset-all completes in about 3.14 seconds and leaves 17/17 healthy
• real Chromium QA passed homepage, seeded login, account edit, public two-step lookup, wrong-ZIP mismatch, amended-return search/article, Refund Sent notice filter, and 768 px responsive layout; no console warnings/errors or horizontal overflow

Asset dependency

The companion asset submission remains ChilleD/WebHarbor discussion #27. I verified its open commit c936d3ad013343cc69cafa63bf0d7dad102f85a7 and downloaded irs_refund.tar.gz with SHA-256 d23cf6ffe1db6b3baefebf299288ebbb09d783a016d2a5c7078647cafcd5a4a9; the archive contains the seed DB plus image/cache directories used for the full build. That HF change should be merged and pinned before this environment is treated as self-contained.