test(wasm): bound the engine and combined gzip budgets at gross growth

[devin-ai-integration]

What and why

develop at 4ce0260 (#884, grid view and relationship matrix) is over the combined WebAssembly budget #970 set. On CircleCI's cimg/go:1.25-node image the gzipped js build of sysml-wasm is 8,355,865 bytes against the 8,350,000-byte budget, so TestWasmRuns/js/fits_the_combined_size_budget fails the Go gates and binaries and Go coverage shards jobs of every develop pipeline from 3835 on; sysml-engine is 7,686,608 against 7,700,000. A GitHub runner builds the same tree about 11 KB smaller (8,344,612 / 7,686,149), which is why the pull-request WebAssembly gate passed. Before #884 the figures were 8,329,707 / 7,662,571 on CircleCI and 8,314,894 / 7,656,349 on GitHub.

The size as it stands is accepted, and the budgets stop moving 50 KB with each feature (#970 and its predecessors): they now bound gross growth only, keeping the combined build under 10 MB with the engine bounded proportionally.

• tests/wasm/combined_test.go: combinedGzipBudget 8,350,000 → 10,000,000
• tests/wasm/engine_test.go: engineGzipBudget 7,700,000 → 9,000,000
• changes/unreleased/wasm-size-budgets.changed.md: a second list item, since test(wasm): raise the engine and combined gzip budgets by 50 KB #970's fragment is still unreleased and the release notes should carry one budget entry

TestEngineDependencies is the gate that keeps a forbidden dependency out of the engine now that the size bound is loose.

How it was verified

Fail-first is the CircleCI measurement above: the local toolchain builds smaller than cimg/go:1.25-node (as GitHub's runners do), so a local run of the old budget is not evidence either way — on this machine the same tree gzips to 8,345,131, 5 KB under the old budget.

After the edit, go test -count=1 -v -run 'TestWasmRuns|TestEngineDependencies|TestBrowserREPL' ./tests/wasm (go1.25.11, Node v24.19.0, so the js subtests ran):

engine_test.go:164: gzipped sysml-engine.wasm is 7686326 bytes, under the 9000000-byte budget
syntax_test.go:173: gzipped sysml-syntax.wasm is 1482873 bytes, under the 1540000-byte budget
core_test.go:195: gzipped sysml-core.wasm is 5968789 bytes, under the 6300000-byte budget
combined_test.go:155: sysml-wasm.wasm is 33646608 raw bytes and 8345131 bytes gzipped -9
--- PASS: TestBrowserREPLWalkthroughs (30.28s)
--- PASS: TestEngineDependencies (0.34s)
--- PASS: TestWasmRuns (108.33s)
ok  	github.com/Open-MBEE/OpenSysML/tests/wasm	138.968s

TestEngineDependencies still bites: with a one-off, reverted _ "github.com/Open-MBEE/OpenSysML/internal/frontend/stdiorpc" import added to cmd/sysml-engine/main.go, go test -count=1 -run TestEngineDependencies ./tests/wasm fails with forbidden dependency in wasip1 build: google.golang.org/grpc/... and google.golang.org/protobuf/... lines (and the js build likewise) in 0.4 s.

Also: go build ./..., go vet ./tests/wasm/..., gofmt -l tests (prints nothing), python3 scripts/changelog.py check.

Checklist

• go build ./..., go vet ./tests/wasm/..., gofmt -l tests and the tests/wasm gate pass locally
• Tests added or updated for the change
• Documentation extended where it already covers the surface (no doc states these budgets)
• Changelog entry added as changes/unreleased/<slug>.<section>.md, not as an edit to CHANGELOG.md
• No gate count moved, so no baseline or make docs-counts run
• No internal work-item labels in the body, docs, or changelog

Link to Devin session: https://nasa-jpl-demo.devinenterprise.com/sessions/c5331dc511a342859cad8a88d46fa210
Open in Devin Desktop: https://nasa-jpl-demo.devinenterprise.com/desktop/session/c5331dc511a342859cad8a88d46fa210?variant=devin
Requested by: @HuiJun

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring

[devin-ai-integration]

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