ci probe: tier1-spike4 isolation (do not merge)

[ryansolid]

Attribution probe for #2923's CodSpeed result (merge-mixed −28%, alongside merge-static ×2.2 / reconcile +92% / update1to1 +5.5% improvements). Isolates one spike. Closes after CodSpeed reports.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 335838e

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

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Click here to learn what changesets are, and how to add one.

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[github-actions]

size-limit report 📦

Path	Size
signals: core floor (createSignal/Memo/Effect/Root/flush)	6.59 KB (-0.45% 🔽)
signals: + createStore	11.21 KB (+0.08% 🔺)
signals: + isPending/latest	8.09 KB (-1.07% 🔽)
app: render + one signal (the simple-app floor)	9.17 KB (-0.31% 🔽)
app: CSR with Show/For/Loading/Errored/lazy	11.21 KB (+0.06% 🔺)

[coveralls]

Coverage Report for CI Build 29784309482

Warning

No base build found for commit 2bf022e on next.
Coverage changes can't be calculated without a base build.
If a base build is processing, this comment will update automatically when it completes.

Coverage: 75.328%

Details

• Patch coverage: No coverable lines changed in this PR.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

Requires a base build to compare against. How to fix this →

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Coverage Stats

Relevant Lines:	778
Covered Lines:	626
Line Coverage:	80.46%
Relevant Branches:	592
Covered Branches:	406
Branch Coverage:	68.58%
Branches in Coverage %:	Yes
Coverage Strength:	14.11 hits per line

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💛 - Coveralls

[codspeed-hq]

Merging this PR will improve performance by 91.81%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 120 untouched benchmarks

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	reconcile: deep tree, 10 of ~12k paths subscribed	6.4 ms	3.3 ms	+91.81%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing probe/tier1-spike4 (335838e) with next (2bf022e)}

[ryansolid]

Probe result: clean — stashedOptimisticReads deletion in isolation passes the CodSpeed gate (1 improvement, 0 regressions). Confirms the merge-mixed movement on #2923 is entirely the affects-channel change (#2924).