Fix coverage-instrumented trampolines

[steipete]

Summary

• prevent coverage instrumentation from clobbering argument registers before naked trampoline assembly runs
• make macOS and simulator destinations explicit/current on hosted runners
• keep the existing large-struct regression test active under code coverage

This unblocks the Xcode checks needed by #42.

Proof

• swift test
• swift test -c release
• full macOS arm64 and x86_64 Xcode test suites with code coverage
• full iOS simulator Xcode test suite with code coverage
• watchOS simulator build
• arm64 disassembly starts with trampoline register saves; no profiling prologue
• $autoreview: clean

Local tvOS execution was unavailable because the installed Xcode lacks the tvOS platform component. The destination now uses the current Apple TV device name and is covered by hosted CI.

[clawsweeper]

Codex review: needs maintainer review before merge. Reviewed June 11, 2026, 4:48 AM ET / 08:48 UTC.

Summary
Review failed before ClawSweeper could summarize the requested change.

Reproducibility: unclear. The review failed before ClawSweeper could establish a reproduction path.

Review metrics: none identified.

Merge readiness
Overall: 🌊 off-meta tidepool
Proof: 🌊 off-meta tidepool
Patch quality: 🌊 off-meta tidepool
Result: rating does not apply to this item.

Overall follows the weaker of proof and patch quality, so missing proof can cap an otherwise strong patch.

Risk before merge

• [P1] No close action taken because the review did not complete.

Maintainer options:

1. Decide the mitigation before merge
   Retry the Codex review after fixing the execution failure.
2. Pause or close
   Do not merge this PR until maintainers decide whether the risk is worth taking.

Next step before merge

• Review did not complete, so no work-lane recommendation was made.

Review details

Best possible solution:

Retry the Codex review after fixing the execution failure.

Do we have a high-confidence way to reproduce the issue?

Unclear. The review failed before ClawSweeper could establish a reproduction path.

Is this the best way to solve the issue?

Unclear. Retry the review first so ClawSweeper can evaluate the actual issue and fix direction.

AGENTS.md: unclear because the file could not be read completely.

Codex review notes: model internal, reasoning high; reviewed against 04e393dd1480.

Label changes

Label changes:

• add rating: 🌊 off-meta tidepool: Overall readiness is 🌊 off-meta tidepool; proof is 🌊 off-meta tidepool and patch quality is 🌊 off-meta tidepool.

Label justifications:

• rating: 🌊 off-meta tidepool: Overall readiness is 🌊 off-meta tidepool; proof is 🌊 off-meta tidepool and patch quality is 🌊 off-meta tidepool.

Evidence reviewed

What I checked:

• failure reason: retryable codex transport failure.
• codex failure detail: Codex review failed for this PR with exit 1.
• codex stderr: ummary":"No target-repository AGENTS.md was found."},"reviewFindings":[],"securityReview":{"status":"cleared","summary":"The diff does not add dependencies, third-party action refs, permissions, secrets access, or new executable downloads.","concerns":[]},"realBehaviorProof":{"status":"insufficient","summary":"The PR reports coverage-enabled Xcode runs and disassembly checks, but no terminal output or linked artifact is available to inspect; add redacted proof, then update the PR body for automatic re-review or ask a maintainer to comment @clawsweeper re-review.","evidenceKind":"none","needsContributorAction":true},"prRating":{"proofTier":"D","patchTier":"B","overallTier":"D","summary":"The implementation is small and plausible, but the required after-fix runtime proof is only asserted rather than inspectable.","nextSteps":["Attach redacted coverage-enabled Xcode output and ARM64 disassembly showing register saves as the first instructions.","Show hosted CI success across the Xcode matrix after the destination changes."]},"telegramVisibleProof":{"status":"not_needed","summary":"This PR does not touch Telegram behavior."},"mantisRecommendation":{"status":"not_recommended","scenario":"none","reason":"Terminal and disassembly artifacts are the appropriate proof for this low-level runtime and CI change.","maintainerComment":""},"featureShowcase":{"status":"none","reason":"This is a targeted bug fix, not a new user-facing.
• codex stdout: No stdout captured.

Likely related people:

• unknown: Codex failed before it could trace repository history. (role: review did not complete; confidence: low)

What the crustacean ranks mean

• 🦀 challenger crab: rare, exceptional readiness with strong proof, clean implementation, and convincing validation.
• 🦞 diamond lobster: very strong readiness with only minor maintainer review expected.
• 🐚 platinum hermit: good normal PR, likely mergeable with ordinary maintainer review.
• 🦐 gold shrimp: useful signal, but proof or patch confidence is still limited.
• 🦪 silver shellfish: thin signal; proof, validation, or implementation needs work.
• 🧂 unranked krab: not merge-ready because proof is missing/unusable or there are serious correctness or safety concerns.
• 🌊 off-meta tidepool: rating does not apply to this item.

Shiny media proof means a screenshot, video, or linked artifact directly shows the changed behavior. Runtime, network, CSP, and security claims still need visible diagnostics.

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