feat(formal): add where.mjs, the contract lookup command

[lan17]

Phase 3 of #220, item N1. One commit, base main. Independent of the other open PRs.

What

node formal/tools/where.mjs C45
node formal/tools/where.mjs C45.maximum-age-exclusive --json

prints, for one contract or one semantic case, where it is:

• Stated: its CONTRACTS row (with the evidence column) and every Quint comment that cites the ID, as file:line, plus the reviewed guides that name it.
• Tested: the semantic cases that carry it, each with its scenarios, scoped Quint checks, required witnesses, replayed regressions and vectors; the documentation sections and tests disposed to it in the source audit; the feature families.
• Challenged: the model-fault challenges that name it, with the invariant, the native mutant kind and ID, the reproducer run and the detecting and excluded profile counts.
• Mapped: the native mutants whose case carries it, with the ports they edit, and the Go parity rows for its cases.

For C45 that is 96 lines assembled from eight files in one command; by hand it was the three-read navigation test #220 set for Phase 1, now one read. It adds no data and no gate: everything comes from the catalogs the audit already parses.

Tests

formal-where.test.ts: C45 resolves to its obligation, the kernel citation in recovery.qnt, the known case, challenge and mutant (M01 with TypeScript, Go and Rust edits), parity rows for exactly its cases and disposed sections; a case ID narrows the view and keeps only the challenges mapped through that case's mutant; the rendering has the four sections with file:line locations; an unknown contract, a malformed query and an unknown case are rejected with a one-line message.

Verification

vitest run test/formal-where passes; tsc --noEmit clean; make audit green; node scripts/check-docs.mjs green. The README and AUTHORING entries were re-keyed with --refresh; parity inputs re-pinned.

🤖 Generated with Claude Code

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.73%. Comparing base (093c1c9) to head (d8b4d38).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #236   +/-   ##
=======================================
  Coverage   93.73%   93.73%           
=======================================
  Files          78       78           
  Lines       11357    11357           
  Branches      656      656           
=======================================
+ Hits        10645    10646    +1     
+ Misses        642      641    -1     
  Partials       70       70           

Flag	Coverage Δ
go	91.17% <ø> (+0.05%)	⬆️
python	92.08% <ø> (ø)
rust	94.29% <ø> (ø)
typescript	96.56% <ø> (ø)

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