chore(deps): align zod across installs and guard against version skew

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

README.md

@@ -37,7 +37,7 @@ inspector/
 │   ├── react/        # React hooks over the state stores
 │   └── storage/      # File I/O helpers for the OAuth persist backends
 ├── test-servers/     # Composable MCP test servers + fixtures used by integration tests
-├── scripts/          # Root build/verify tooling (install cascade, smokes, verify-build-gate, verify-format-coverage, pack:verify)
+├── scripts/          # Root build/verify tooling (install cascade, smokes, verify-build-gate, verify-format-coverage, verify-dep-lockstep, pack:verify)
 ├── docs/             # Task-oriented guides (server configuration, MCP App review, launcher/config plan)
 ├── specification/    # Design/build specifications
 ├── AGENTS.md         # Contribution rules for agents AND humans (see below)
@@ -263,13 +263,14 @@ Each client self-validates from its own folder; the root scripts chain them. The
 
 | Script                | What it does                                                                                                                                                                                                                                              |
 | --------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `npm run validate`    | Runs `verify:format-coverage` (asserts every tracked source file is format-gated) first, then `validate:core` (the shared `core/` `format:check` + `lint` gate), then per client: `format:check` + `lint` + **`typecheck`** (cli/tui only) + `build` + fast unit tests. The quick inner-loop check.                                          |
+| `npm run validate`    | Runs `verify:format-coverage` (asserts every tracked source file is format-gated) first, then `verify:typecheck-coverage` and `verify:dep-lockstep`, then `validate:core` (the shared `core/` `format:check` + `lint` gate), then per client: `format:check` + `lint` + **`typecheck`** (cli/tui only) + `build` + fast unit tests. The quick inner-loop check.                                          |
 | `npm run coverage`    | The **per-file ≥90% gate** (lines/statements/functions/branches) under v8 instrumentation, per client. CI-enforced. For web this also runs the integration project and covers the shared `core/` runtime (including `core/json` and `core/client`).       |
 | `npm run smoke`       | End-to-end smokes through the built launcher (`--help` dispatch + prod cli/tui/web), plus two headless-Chromium smokes: a boot smoke that runs the prod web bundle and asserts a clean first render (no uncaught error — sync exception or unhandled rejection, how a Node built-in reaching the browser bundle manifests), and an **MCP Apps** smoke (`smoke:web:app`) that drives connect → open app → `data-app-status="ready"` against a composable App server, covering the sandbox proxy and UI-protocol bridge.                               |
 | `npm run verify:build-gate` | Runs a real `vite build` with a Node built-in forced into the browser graph and asserts the build **fails** via the #1769 gate (which turns Vite's browser-externalization warning into a hard error). Guards against the warning phrasing drifting in a Vite bump and silently disabling the gate. Part of `npm run ci`.                        |
 | `npm run verify:format-coverage` | Parses the `format:check` globs out of every `package.json` (only those reachable from `validate`), enumerates all tracked source files, and **fails** listing any not covered by a glob — the durable guard for the "every first-party source file is format-gated" invariant (#1792). Runs first in `validate`.                        |
-| `npm run test:scripts` | Table-driven unit tests (`node --test`) for the guard's own pure parsers (`scripts/lib/npm-scripts.mjs` + the exported helpers of `verify-typecheck-coverage.mjs`), one case per rule they encode. Runs in `validate` — and `verify:typecheck-coverage` guards *this* gate in turn (reachable from `validate`, non-empty test set, every test file matched by the `test:scripts` glob), since `node --test` silently skips a file its glob misses and still exits 0. |
+| `npm run test:scripts` | Table-driven unit tests (`node --test`) for the guard's own pure parsers (`scripts/lib/npm-scripts.mjs` + the exported helpers of `verify-typecheck-coverage.mjs` and `verify-dep-lockstep.mjs`), one case per rule they encode. Runs in `validate` — and `verify:typecheck-coverage` guards *this* gate in turn (reachable from `validate`, non-empty test set, every test file matched by the `test:scripts` glob), since `node --test` silently skips a file its glob misses and still exits 0. |
 | `npm run verify:typecheck-coverage` | The typecheck-coverage analog of the above (#1791): for each Node client (auto-discovered from disk — enrolled via its `typecheck` script's projects, or for a `tsc -b` client like `clients/web` via its `tsconfig.json` `references`) it runs those projects with `tsc --listFilesOnly`, unions them, and **fails** listing any tracked `.ts`/`.tsx`/`.mts`/`.cts` under the client that lands in no project (so a new top-level config/helper can't silently go untypechecked). It also requires, deny-by-default, the first-party TS no client owns (`test-servers/src`, the root `vitest.shared.mts`, all of `core/`, and any new top-level location) to land in some client project's tsc pass — so a `core` `*.tsx` web's projects don't reach is caught too. Also asserts the gate is wired (each client's typecheck pass — its `typecheck` script, or web's `tsc -b` — is reachable from its `validate`, and the root chain runs each client's `validate`). Runs in `validate`.                        |
+| `npm run verify:dep-lockstep` | Guards the "one version per install-crossing dependency" invariant (#1896). v2 is not a workspace, so a client's test project compiles `core/` and `test-servers/src` — which resolve from the **root** install — alongside the client's own sources, putting the same package in one `tsc` program twice. At the same version that's harmless; skewed, TypeScript must relate two structurally-distinct copies of every type, which for a recursive-generic surface is exponential (zod `4.3.6` vs `4.4.3` exhausted the 4GB tsc heap in `clients/web`). 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. Runs in `validate`. |
 | `npm run ci`          | **Mandatory pre-push command.** `validate` → `coverage` → `verify:build-gate` → `smoke` → Storybook. A true superset of GitHub CI.                                                                                                                        |
 | `npm run pack:verify` | Publish smoke — see [Publishing](#publishing).                                                                                                                                                                                                          |