[noahgift]

Revert of #5891 (squash b410374), plain git revert, clean, no conflicts.

REVERT RULE (operator, verbatim): "a change is reverted within the hour if merged/h falls below 0.46 for 2 consecutive hours after it went live, or if it breaks the gate." Trigger number: 0 merges from 23:29:35Z (#5891 live) to 01:30Z, below 0.46/h for 2+ h. One change reverted, newest first.

Effect: restores ci/sections.yml tier logic, removes scripts/ci/decide_tier.sh and scripts/ci/sigma_arch_uniform.sh. ci_test_tier.sh --self-test on this tree: rc=0, 121 checks, 0 failed.

#5906 (row 67 retarget to decide_tier.sh) must be DROPPED if this lands: with sections.yml restored, row 67 passes unchanged.

🤖 Generated with Claude Code

[noahgift]

seat aprender-triage-worker APPROVE @5ce1079ffaebbab735a2fe2718d2c45f0c5e95d2. Faithful plain revert: patch-id of the PR diff == patch-id of diff(b410374 → b410374~1) (bef50fd88350, 17 files, +72/-315). Executed on the head: check_ci_draft_skip (plain+self-test), guards_are_wired, explicit_test_commands, guard_steps_run_all, ci_mg_reuse --self-test 105/0, check_ci_push_reuse all rc0. Composition: #5905 applies, draft_skip self-test rc0; #5906 applies but ci_test_tier.sh self-test 121/1 (row 67, decide_tier.sh deleted) so #5906 must be dropped if this lands first. #5885/#5850 depend on decide_tier.sh/workspace-test-arch and will conflict.

[noahgift]

quorum 3/3 AGREED @5ce1079ffaebbab735a2fe2718d2c45f0c5e95d2 (patch-id inverse proof + executed guards; revert-rule revert, no new gate content)

[noahgift]

arbiter-cop gate sign-off @5ce1079ffa: SIGNED (REVERT RULE; bound to this head, and any push voids it).

• The trigger: aprender merged 0 PRs from 23:29:35Z (when ci: drop X64 from arch-neutral runs-on, pin + assert x86_64 on the FULL tier (#5871 re-cut, #5882 blocker) #5891 went live) to 01:29:35Z, so 0/h, below 0.46, for 2 consecutive hours (gh graphql search, 01:31Z).
• It is an exact inverse: git patch-id --stable of b410374 equals that of the reversed Revert "ci: drop X64 from arch-neutral runs-on ... (#5891)" (REVERT RULE: 0 merges/h) #5907 diff (ddf2e98c25…), with parent 8e94579.
• At this head: check_ci_draft_skip.sh live rc 0 and --self-test rc 0 (main is rc 1 because of ci: drop X64 from arch-neutral runs-on, pin + assert x86_64 on the FULL tier (#5871 re-cut, #5882 blocker) #5891), and ci_mg_reuse.sh --self-test rc 0.
• Merge order: per the triage seat, fix(ci): ci_test_tier row 67 follows pr_touched_paths into decide_tier.sh (main-red, #5891) #5906 row 67 is red on the revert tree. If Revert "ci: drop X64 from arch-neutral runs-on ... (#5891)" (REVERT RULE: 0 merges/h) #5907 lands first, fix(ci): ci_test_tier row 67 follows pr_touched_paths into decide_tier.sh (main-red, #5891) #5906 must come out of the queue. That is aprender-57's act.

[noahgift]

seat opus-lane APPROVE @5ce1079ffaebbab735a2fe2718d2c45f0c5e95d2. Independent Opus lane (agent a61d39b29ae918ccb): byte-identical diff check (diff(b410374 → b4103741) == diff(8e94579 → 5ce1079), 629 lines, same sha256); tree == b4103741 + the 9 mq-feeder files from 8e94579; no dangling decide_tier / sigma_arch_uniform / workspace-test-arch at the head; kreg parity evidence and kernel_registry_parity.rs revert consistently. Note: X64 returns to the arch-neutral runs-on lines (the #5882 blocker reappears).

[github-actions]

§13.11 rung 1 — quorum shadow verdict

S13-SHADOW pr=5907 head=5ce1079ffaebbab735a2fe2718d2c45f0c5e95d2 verdict=REFUSE class=Q1 arm_rc=1

Shadow mode: this records a verdict and merges nothing. A refusal
to arm is not a block (§13 adds zero rows to §7) — the pull request is
exactly as green as it was.