Allow the @intX 0.3.0 line (#8)

The peer ranges pinned ^0.2.2, so a host on the current Interchange line cannot
satisfy them without a package-manager override.

Every symbol this package imports from @intX is unchanged in 0.3.0:

  @intx/hub-api   idResource, RequireGrant, TenantEnv, createRequireGrant
  @intx/authz     createInMemoryGrantStore (tests)
  @intx/types     isAllowedMimeType

dist/middleware/grant.d.ts is byte-identical between 0.2.2 and 0.3.0, TenantEnv
is unchanged, and @intx/authz's index only gains exports — authorizeAction,
toolConsumer, EvalOptions — none removed. ATTACHMENT_ALLOWLIST still carries the
same 22 media types, so the type isAllowedMimeType narrows to is the same.

Verified on 0.3.0: tsc --noEmit clean, dep-guard clean. The Postgres-backed
suite is unchanged — 17 pass / 41 fail both before and after, the failures being
the harness refusing to run without a live allowlisted database.

Author: TheGreatAxios