Closes#1896
`clients/web`'s `tsc -b` exhausted the 4GB default heap at zod 4.4.x. The
cause is not a zod regression nor a pathological inference site of ours: it
is two copies of zod at *mismatched versions* inside one tsc program.
`clients/web/tsconfig.test.json` compiles `test-servers/src`, whose files
resolve zod (and the SDK's zod) from the **root** install, alongside web's
own sources, which resolve from `clients/web/node_modules`. At 4.3.6 vs
4.4.3 TypeScript must relate two structurally-distinct declarations of every
`@modelcontextprotocol/*` schema type, which is exponential over a recursive
generic surface — `TS2589 Type instantiation is excessively deep`, then OOM.
Bumping root zod to 4.4.3 and changing nothing else returns the build to
baseline: 11.4s and 2,567,882 instantiations, against 11.2s / 2,567,503 at
4.3.6. Two copies at the same version are harmless; skew is what explodes.
So drop the `~4.3.6` hold on `clients/web` and move all four manifests and
lockfiles to zod 4.4.3 together, and add `verify:dep-lockstep` to `validate`
to keep them there. The guard derives its candidate set from what `core/`
and `test-servers/src` import, compares the committed lockfiles' top-level
entries, and fails deny-by-default on any skew not in the annotated
`TOLERATED_SKEW` allowlist. It joins the existing mutual-vouch ring so
dropping it from `validate` is caught by `verify:format-coverage`.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
6c33da38c9