fix(node): propagate fs path mutator errors

[andrewtdiz]

Linked issues

Closes #2733
Closes #2735
Closes #2737
Closes #2738
Closes #2740

Summary

This PR fixes a focused node:fs error-propagation cluster for deterministic path and path-pair filesystem failures:

• readlink now throws/callbacks/rejects real fs errors instead of returning an empty target.
• rename, copyFile, link, and symlink now preserve Node-style Error fields across sync, callback, and node:fs/promises surfaces.
• Two-path syscall errors now expose err.dest alongside err.code, err.syscall, and err.path.
• The fs parity gap docs and fs suite status are updated for the APIs covered here.

Why these were batched

These issues share the same runtime path: sentinel-returning fs mutators, callback wrappers that previously reported success after failed syscalls, and fs/promises thunks that need to reject with the same error objects. Batching them keeps the side-table/error-object changes and parity fixture in one coherent fs PR.

Tests added

• Added test-parity/node-suite/fs/path-mutator-errors.ts, covering sync, callback, and node:fs/promises behavior for missing paths, invalid readlink targets, missing destination parents, COPYFILE_EXCL, existing symlink destinations, and success sanity checks.

Verification

• TMPDIR="$PWD/target/tmp" PATH=/home/github-runner/actions-runner/externals/node24/bin:$PATH ./run_parity_tests.sh --suite node-suite --module fs --filter path-mutator-errors - pass
• TMPDIR="$PWD/target/tmp" PATH=/home/github-runner/actions-runner/externals/node24/bin:$PATH ./run_parity_tests.sh --suite node-suite --module fs - 126 pass, 0 fail
• TMPDIR="$PWD/target/tmp" PATH=/home/github-runner/actions-runner/externals/node24/bin:$PATH ./run_parity_tests.sh --suite node-suite --module fs-promises - 62 pass, 0 fail
• TMPDIR="$PWD/target/tmp" CARGO_BUILD_JOBS=1 RUSTC_WRAPPER= cargo check -p perry-runtime -p perry-codegen -p perry-api-manifest - pass with existing warnings
• TMPDIR="$PWD/target/tmp" CARGO_BUILD_JOBS=1 RUSTC_WRAPPER= cargo test -p perry-runtime fs:: - 2 pass, 0 fail
• cargo fmt --all -- --check - pass
• git diff --check HEAD - pass
• ./scripts/check_file_size.sh - pass

Known limitations

• The new fixture pins stable Error fields, not full platform-specific message text or numeric errno values.
• Broader fs error parity for unrelated APIs remains tracked separately.

Non-goals

• No changes to fs.watch, FileHandle semantics, stream behavior, or callback scheduling semantics.