fix(buffer): expose namespace constructors and backing properties

[andrewtdiz]

Closes #3387.
Closes #3385.
Closes #3386.

Summary:

• Export Blob from node:buffer and preserve namespace/global Blob and File constructor aliases through native constructor lowering.
• Register direct new buffer.Blob(...) / new buffer.File(...) results as Blob/File native instances so properties and methods keep the existing fetch-backed behavior.
• Materialize stable ArrayBuffer backing aliases for Buffer .buffer / .parent, including registered view offsets for .byteOffset / .offset.
• Add focused node-suite fixtures for namespace constructors, backing properties, parent aliases, view offsets, and ArrayBuffer write-through.

Why batched:

• node:buffer: namespace-bound Blob and File constructors lose native behavior #3385 and node:buffer: Buffer backing properties are missing on Buffer instances #3386 share the same node:buffer namespace/runtime property surface, and node:buffer: module namespace and backing property parity cut #3387 is the umbrella cut for those compatibility gaps.

Verification:

• RUSTC_WRAPPER= cargo build --release -p perry -p perry-runtime -p perry-stdlib
• PATH=/home/github-runner/actions-runner/externals/node24/bin:$PATH RUSTC_WRAPPER= ./run_parity_tests.sh --suite node-suite --module buffer --filter namespace-constructors (PASS, test-parity/reports/parity_report_20260530_170453.json)
• PATH=/home/github-runner/actions-runner/externals/node24/bin:$PATH RUSTC_WRAPPER= ./run_parity_tests.sh --suite node-suite --module buffer (PASS 131, fail 0, compile fail 0, skipped 0; test-parity/reports/parity_report_20260530_170504.json)
• PATH=/home/github-runner/actions-runner/externals/node24/bin:$PATH RUSTC_WRAPPER= ./run_parity_tests.sh --filter test_parity_buffer (PASS, test-parity/reports/parity_report_20260530_170754.json)
• RUSTC_WRAPPER= cargo check -p perry-hir -p perry-runtime -p perry-stdlib -p perry-codegen
• cargo fmt --all -- --check
• git diff --check
• ./scripts/check_file_size.sh

Notes:

• This does not redesign Buffer storage or pooling; it routes the Node-compatible backing-property surface through the existing registered Buffer/view alias machinery.

[andrewtdiz]

Pushed the same CI-only fix for the cargo-test ENOSPC failure. The failed job ran out of disk building perry-ext-ws; this branch now reduces cargo-test artifact size and prunes package artifacts after each package test.\n\nLocal verification:\n- workflow YAML parsed successfully\n- git diff --check

[andrewtdiz]

Fixed the cargo-test failure from the latest run.

This branch predates the HIR changes that now exist on main, so the duplicate stable-hash tags only appeared in GitHub's PR merge ref. I merged origin/main into the branch, then applied the same RegExpEscape stable-hash tag fix used on #3414.

Local checks passed: CARGO_TARGET_DIR=/root/perry/target cargo test -p perry-hir stable_hash::tests::expr_variant_stable_hash_tags_are_unique, cargo fmt --all -- --check, git diff --check HEAD~2..HEAD, git diff --check, and scripts/check_file_size.sh.