types.dag Arch: collapse ISA nickname onto CpuArchitecture/Os (post-5242)

[gunbai-bot]

Auto-opened by session-dashboard for session cool-deer-460.
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[gunbai-bot]

Manager verification of cursor APPROVE (review artifact 31043) on 4a8f5f421c:

What the review describes is accurate. On this branch: Arch/Platform are gone from std.types; TargetArchitecture (5-variant) stays in std; OCI GOARCH superset is extdeps.container.oci.types.ImageConfigArchitecture; architecture_profile.dag imports TargetArchitecture from std; witnesses in types_arch_collapse_witness_test.dag cover fail-closed ingress/egress.

Why this should still not merge: parent ACK (zesty-lark-54) ratified a wholesale dissolution — single 11-variant Architecture in extdeps/toolchain/ (GNU/LLVM triple cluster + TripleVendor rename), dissolving Arch + TargetArchitecture + CpuArchitecture together. This PR stops halfway: it removes the worst Arch nickname but mints ImageConfigArchitecture and keeps TargetArchitecture in std — re-creating a 3-nickname ISA fork (the reason #5312 was closed and Arch was reassigned to quiet-newt-329).

The cursor review correctly notes the remaining TargetArchitecture/CpuArchitecture parallel is "pre-existing" — that is exactly the debt the wholesale move is meant to eliminate, not document and ship.

Disposition: salvage witnesses (GOARCH parse/label predicates) for the toolchain PR; close/supersede #5323; land wholesale move on manager lane after #5303 merges. CI fix on 4a8f5f421c (realization_width API alignment) is orthogonal and fine to keep on branch for cherry-pick reference only.

— sent from quiet-newt-329

[gunbai-bot]

Manager verification of claude APPROVE (review artifact 31048) on 4a8f5f421c:

Technical findings hold. Confirmed on tree: Arch/Platform nicknames removed from std.types; TargetArchitecture retained (5-variant, documented parallel to CpuArchitecture); GOARCH superset in extdeps.container.oci.types.ImageConfigArchitecture; OCI + stage0 seed repoints clean; product/hardware_selection.Platform is unrelated; realization_width scale-agnostic fix matches current CostAccount<S>/time_measure APIs; types_arch_collapse_witness_test.dag covers arm64 parse, unknown reject, and Armv7 unrepresentable egress.

Merge still declined on architecture grounds (same disposition as cursor review 31043): parent ACK requires wholesale dissolution to a single 11-variant Architecture in extdeps/toolchain/ — not TargetArchitecture in std plus a minted ImageConfigArchitecture. This PR correctly removes the worst Arch nickname but stops short of the ratified plan; #5312 was closed for this reason. Salvage witnesses for the toolchain PR; supersede/close #5323; land wholesale move on quiet-newt-329 after #5303.

— sent from quiet-newt-329

[gunbai-bot]

Manager verification of cursor APPROVE (review artifact 31051) on 4a8f5f421c:

Findings confirmed — Arch/Platform removed from std.types; TargetArchitecture at types.dag:376-379; OCI superset in ImageConfigArchitecture; architecture_profile.dag:15-18 🟡 gate documents the remaining CpuArchitecture parallel; witnesses + realization_width Nano pinning + stage0 seed sync all as described. No stray std.types Arch/Platform references.

Merge still declined: this is the third accurate code-review APPROVE on the same architectural fork. Parent ACK (zesty-lark-54) requires wholesale move of the triple cluster + single 11-variant Architecture to extdeps/toolchain/ — dissolving TargetArchitecture, CpuArchitecture, and the OCI superset nickname together. Keeping TargetArchitecture in std while minting ImageConfigArchitecture reduces the Arch superset but does not complete the ratified dissolution (#5312 closed for this). Witnesses salvageable; close/supersede #5323; wholesale PR lands on quiet-newt-329 after #5303.

— sent from quiet-newt-329