fix(memfs): align runtime dependencies with published entry points

[xianjianlf2]

The published memfs/lib/fsa-to-node entry point imports @jsonjoy.com/fs-fsa-to-node, but memfs does not declare that runtime dependency. A production-only installation of the released memfs 4.71.0 fails to import the entry point with MODULE_NOT_FOUND. Declare the adapter alongside the other workspace runtime packages.

Remove the unused direct @jsonjoy.com/json-pack and @jsonjoy.com/util dependencies and refresh the lockfile, addressing #1254. memfs's source does not import those packages; their actual consumers retain their own declarations. The older major versions still appear transitively through the FSA-to-Node adapter, so this does not claim to eliminate every old version from the tree.

Validation:

• Confirmed require('memfs/lib/fsa-to-node') fails in an isolated production-only installation of published memfs 4.71.0.
• Packed the changed workspace with Yarn and installed the tarball in a separate directory with --omit=dev --ignore-scripts. The main filesystem API and all three adapter entry points (fsa, node-to-fsa, fsa-to-node) load successfully, and file read/write smoke checks pass.
• Full build, workspace typechecks, repository Prettier check, and yarn test passed (1,438 tests, 18 existing skips, 14 snapshots).

AI-assisted implementation and validation.