#22572 test(cmux-next): TransferProgressGateTests compiles (base red)

TransferProgressGateTests (from #22455) does not compile: TransferProgressGate.admits is mutating, and #expect evaluates its expression on an immutable copy. Every CmuxNext package test build on feat-cmux-next fails at this file, so no focused suite can run. Each result is now read into a let before its #expect. The change is the same as the one in Leo's #22563, split out so other PRs can get test receipts now.

Testing

Command: cmux-ci run --class light --script scripts/ci/package-test-lane.sh --ref <SHA> --arg=suite --arg=Packages/macOS/CmuxNext --arg=<Suite> --env CMUX_CI_XCODE_APP=/Applications/Xcode_26.6.app

• Base (red): ChiefPetMessageTests at c11895e40396 failed to build because of TransferProgressGateTests.swift:22-32 ("cannot use mutating member on immutable value"). Fleet step 66316df5b905017381d05d0c.
• Head: TransferProgressGateTests at 22bd8f27a9d4. The result goes below once the step finishes.

Observed / Not run

• Observed: the base compile failure above.
• Not run: the full CmuxNext test suite.

Changelog

none

🤖 Generated with Claude Code

---

^{Need help on this PR? Tag @codesmith-bot with what you need.}

---

Summary by cubic

Fixes TransferProgressGateTests so every CmuxNext package test build can compile again.

• TransferProgressGate.admits is mutating, and #expect evaluates on an immutable copy; each result is now read into a let first.
• Updates ci-target-graph.json so the budget graph includes the CmuxNextRemoteFetch target.