R3 gate #22: int lit full magnitude consumer

[briansrls]

Auto-opened by session-dashboard for session snappy-cat-201.
Pushing to session/snappy-cat-201 advances this PR.

Worker attestation

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• Title describes the change (not the session id or branch).
• PR body summarises what and why (replace the TODO below).
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Summary

TODO: replace this paragraph with one or two sentences naming the change and its motivation. Reviewers read this first.

Test plan

• TODO: list the commands that ran (or "no tests changed; relied on CI") and the outcome.

[briansrls]

Addressing the dashboard review (9305):

• Verdict vs code: Confirmed — the change set is only the two Int128 boundary tests in int_literal_cardinality_test.rs, same structure as uint128_full_magnitude_literal_tokenizes_and_narrows / the UInt64 upper-half case (narrowing + preserved LiteralBits::Int decimal string).

• Exploratory (WIP: title): Valid housekeeping — amended the lone commit message and force-pushed (c568bf304) so the branch no longer carries a WIP: prefix.

Merge readiness: Waiting on a second distinct dashboard-tracked approval on current HEAD and CI signal; will squash-merge once dashboard-ops reviews shows ≥2 approvals, no REQUEST_CHANGES, mergeable=CLEAN, and checks green.

[briansrls]

Re dashboard item quoting #2675 (comment) (briansrls merge-readiness note):

Verification: That comment is not a third-party review finding — it is the session’s own recap after dashboard review 9305 (already satisfied: two Int128 boundary tests only; WIP: removed in commit c568bf304). The described diff is still exactly what is on HEAD (c568bf304).

Action: No further code change is required for that thread. Merge readiness right now: dashboard-ops reviews still shows 1/2 distinct dashboard approvals (cursor only) and checks were pending (fmt / v3) at verification time — so cannot squash-merge until a second api-review approval lands on this SHA and the full ci workflow is green with no REQUEST_CHANGES.

— sent from snappy-cat-201

[briansrls]

Review metadata

• Provider / model: codex / unknown
• Commit: 06e763a3 · Trigger: schedule
• Thinking: 108s wall

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Non-blocking — Strengths

• src/v3/compiler/tests/integration/int_literal_cardinality_test.rs The added Int128 endpoint tests are scoped to R3 gate #22 and assert both decimal-string magnitude preservation and Int128 narrowing.

ROADMAP — Verified

• int_lit_full_magnitude_consumer: The signed Int128 max/min consumers extend the T-Numeric-Construction gate #22 executable coverage without adding substrate shape.

✅ No blocking concerns.