[c14094071]

Every built-in Mine Level Descent (triangle) case gave the same answer to a correct bottom-up solution, to the sum of each level's minimum, and to a greedy walk that steps to the cheaper child, so both mistakes the problem's own pitfalls name passed all five cases.

This adds two cases to the triangle judge in problem-bank/judges.json, appended after the existing five so the scenario page's examples keep their indexes, and regenerates web/judges/mine-level-descent.json with python3 scripts/gen-problems.py. Each new case puts the cheapest chambers where a crew cannot reach them from each other, and each fails both wrong approaches:

Case	Expected	Bottom-up	Sum of each level's minimum	Greedy smaller child
cheapest values not connected: [[-1],[2,3],[1,-1,-3]]	-1	-1	-2	0
cheaper step misses the deep saving: [[1],[2,3],[4,5,-10]]	-6	-6	-7	7

Both labels are added to the tricky-case list in tests/web/contract.rs, so dropping either case fails static_problem_bank_and_judges_cover_each_problem.

Validation, on Ubuntu 24.04 under WSL:

• ./scripts/test.sh portable passes. Skipped only for missing local tools: commentflow, ruff, shfmt, shellcheck, cargo-audit, actionlint.
• cargo test --locked --test web static_problem_bank_and_judges_cover_each_problem passes.
• In a local make web build of this branch, with C++: the bottom-up solution passes 7/7, and the level-minimum and greedy solutions from Mine Level Descent tests accept solutions that ignore which chambers are reachable #432 each pass 5/7, failing only the two new cases with the values in the table.

Closes #432

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Summary by cubic

Adds two test cases to the triangle judge that catch solutions which ignore reachability, closing #432. Previously, all five cases produced the same answer for a correct bottom-up solution, the sum of each level's minimum, and a greedy walk to the cheaper child, so the two incorrect approaches went undetected. The new cases place the cheapest chambers where the crew cannot reach them from each other, causing both wrong approaches to fail while correct solutions still pass.

^{Written for commit d429ee7. Summary will update on new commits.}

[jserv]

Thank @c14094071 for contributing!