Implement `remove_nodejs_compat_eol_v26` (and 25) for Node 26

[vicb]

We have the 22, 23, and 24 flags to remove EOL Node features in the corresponding releases.

We should add flags for 25 and 26 as well.

Refs:

• https://nodejs.org/en/blog/release/v25.0.0
• https://github.com/nodejs/node/blob/main/doc/changelogs/CHANGELOG_V25.md
• https://nodejs.org/en/blog/release/v26.0.0
• https://github.com/nodejs/node/blob/main/doc/changelogs/CHANGELOG_V26.md

Here is what gemini thinks we should handle (to give an idea):

Node.js 25

🛑 Removed / EOL Features

• Buffer: The legacy SlowBuffer API was finalized and completely removed.
• File System (fs): The legacy file access constants fs.F_OK, fs.R_OK, fs.W_OK, and fs.X_OK were completely removed.
• Process & Async Hooks:
  • The multipleResolves event on the process object was removed.
  • The asyncResource property on bound functions in async_hooks reached EOL.
• Network & URL: The legacy URL parser's tolerance for bad/malformed ports was moved to EOL (developers must strictly use the WHATWG URL() API).
• Testing & Assertions:
  • The experimental CallTracker in the assert module was moved to EOL.
  • Passing multiple arguments to assert.fail() was removed.
• Package Management: Corepack is no longer bundled with Node.js starting from version 25.0.0.

---

Node.js 26

Node.js 26 (released in May 2026) continues the cleanup process and promotes several doc-deprecations to runtime-deprecations or full removals. Note: With the release of Node.js 26, the Node.js 25 release line reached its End-of-Life (EOL) on June 1, 2026.

🛑 Removed / EOL Features

• Legacy Internal Streams: The legacy stream private modules (_stream_wrap, _stream_readable, _stream_writable, _stream_duplex, _stream_transform, and _stream_passthrough) are now fully removed.
• HTTP (DEP0063): http.Server.prototype.writeHeader() is fully removed. Developers should use http.Server.prototype.writeHead() instead.
• Transform Types: The --experimental-transform-types CLI flag has been removed.
• Web Storage API: localStorage now returns undefined if accessed without a properly configured backing file.