Package maps land; Buffer.copy gets faster

Experimental package maps for module resolution (2f2b810) Node now supports --experimental-package-map, letting bare specifier resolution consult a JSON package map to control which packages may import which dependencies. The change adds new docs, error codes, CLI flag plumbing, resolver logic, and extensive tests, so it’s a significant new module-resolution feature.

Buffer.prototype.copy now uses V8 byte-copy APIs (4383f67) Buffer copies are routed through V8’s new CopyArrayBufferBytes APIs instead of manually materializing views and memmove-ing bytes in Node. This should improve partial-copy performance and also makes copies correctly return 0 when the target backing store is detached or immutable.

Other misc changes

• Added V8 CopyArrayBufferBytes APIs and bumped the embedder patch version (d66c3a6).
• Removed a redundant AIX shared-library intermediate target from the build (11390b5).
• Hardened a few GitHub Actions shell invocations and PR-url linting (144f795).
• Fixed two documentation typos (20fda56, 8c43981).