Per-package lint:types silently skips via stale tsbuildinfo; ~100 latent type errors in ocapn/thixotrope tests

[kumavis]

Summary

While chasing the lint CI failure on #786 we found that per-package yarn workspace <pkg> lint (which chains lint:types) had been passing locally only because stale incremental build state (tsconfig.tsbuildinfo and previously emitted .d.ts files) made tsc treat everything as up to date and skip re-checking. From a genuinely clean tree, lint:types fails with roughly 100 pre-existing errors:

• @endo/ocapn: 78 errors, all in test/**
• @endo/thixotrope: 22 errors, all in test/**

Reproduction

yarn clean
yarn workspace @endo/ocapn lint       # 78 type errors
yarn workspace @endo/thixotrope lint  # 22 type errors

Before yarn clean, both commands pass — same tree, same sources.

Why CI does not catch it

The CI lint job runs root prettier/eslint/shellcheck, yarn docs, root tsc -p tsconfig.json --noEmit, and yarn build:types. All of those are green (the root program and the composite build apply different settings and, for build:types, exclude test files). No CI job runs per-package lint:types, so the checked-in state drifted.

The dominant error pattern

Almost every error is the same shape: an eventual-send call on a presence typed as bare object, e.g.

test/hub.test.js(183,39): error TS2339: Property 'fetch' does not exist on type 'object'.

driven by presence-returning signatures such as Session.getBootstrap being declared () => object (packages/ocapn/src/client/types.js), so E(session.getBootstrap()).fetch(...) fails. Source files avoid it with per-call-site /** @type {any} */ casts (see client/sturdyrefs.js); the test files never got the casts.

Possible fixes

1. Widen the handful of presence-returning signatures (getBootstrap, getRemoteBootstrap, resolver/import providers) from object to any (or a dedicated RemotePresence alias). A remote presence's methods are only known to the caller, which invokes them through E(), so object provides no real checking today — it just forces casts. This fixes all ~100 errors in a few lines and lets the existing source-side casts be removed.
2. Cast at each of the ~100 test call sites, keeping the narrow public types.
3. Either way, consider adding per-package lint:types (from clean state) to CI, since a gate that only passes with warm build state is not a gate.

Option 1 + 3 seems right; opinions welcome.

@kriscendobot could you review this diagnosis and weigh in on options 1–3?

Found during #786 (rebase onto llm); the head of that branch is green on the gates CI does run.