docs(spec): clarify TypeScript integer waiver

[lntutor]

Summary

• clarify that Node 22 reviver source access makes lossless integer decoding technically feasible
• retain the TypeScript waiver because returning bigint would break the public number-typed API
• keep the rubric, specification, and conformance test description consistent

Verification

• python3 -m json.tool rubric-audit.json
• python3 -m json.tool conformance/tests/integer-precision.json
• verified lossless context.source decoding on Node 22.22.0
• git diff --check

Release notes: Documentation

Closes #533

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Summary by cubic

Clarifies the TypeScript integer precision waiver: Node >=22.12 can access raw digits in a JSON.parse reviver, making lossless bigint decoding feasible, but we retain the waiver because returning bigint would break the number-typed API. Syncs SPEC.md, the integer-precision conformance test description, and the rubric note.

^{Written for commit ff13a09. Summary will update on new commits.}

[Copilot]

Pull request overview

Clarifies why TypeScript retains its integer-precision waiver despite Node 22 supporting lossless decoding.

Changes:

• Documents JSON.parse reviver source access.
• Explains the number-to-bigint API compatibility concern.
• Aligns the specification, rubric, and conformance description.

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Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
SPEC.md	Clarifies the retained TypeScript precision limitation.
rubric-audit.json	Updates waiver 1B.6 rationale.
conformance/tests/integer-precision.json	Aligns the conformance-test description.

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[jeremy]

Reviewed as maintainer against post-#535 main:

• Accuracy: The Node >=22.12 claim matches what we verified empirically in #533 — JSON.parse reviver context.source yields the raw digits, so lossless bigint decode is feasible on the supported engine floor. The rewrite correctly retains waiver 1B.6 on its surviving ground (bigint would break the number-typed API surface) and promises no SDK adoption.
• Consistency: All four sites from #533 are covered or verifiably fine — SPEC §10 conflict marker and the per-language precision table are updated here; the §19 waiver-table row (| 1B.6 | §10 | 64-bit integer precision |) is index-only with no stale claim; the §19 TS skip-roster line ("Number is 53-bit") stays factually consistent with the new text.
• Scope: integer-precision.json change is description-only — operation, method, path, and assertions untouched.

Thanks for threading this precisely through the spec, rubric, and conformance description.

[jeremy]

Merged as d3422f5. Thank you for a first contribution that hit exactly the right altitude: you took the "decide and document" ask from #533, made the call the evidence supports (waiver retained on API-surface grounds, not mechanism grounds), and threaded it consistently through the spec, the rubric, and the conformance description without touching any test semantics. That is precisely how we hoped that issue would land. Welcome, and we would be glad to see you back.