fix: unwrap ESM-style process polyfills in internal streams (fixes #539)

[smessie]

Summary

Some browser bundlers/polyfill setups expose the process/ polyfill as an ES module with a default export (i.e. { __esModule: true, default: <process> }). The internal streams code does const process = require('process/') and then uses process.nextTick(...), which throws in that scenario because the module namespace object has no nextTick.

This routes the internal process/ imports through a small shim that unwraps such ESM-style polyfills (returning the first candidate exposing nextTick) while leaving normal CommonJS polyfills untouched.

Fixes #539.
This PR follows a similar approach as #543.

Changes

• Add lib/internal/shims/process.js (generated from src/) that unwraps an ESM-default process/ polyfill, validating candidates via 'nextTick' in candidate, and falls back to the module as-is otherwise.
• Route the internal streams (destroy, duplexify, end-of-stream, from, pipeline, readable, writable) through the shim instead of require('process/') directly.
• Wired through the repo's build/replacement generation so both the source and generated outputs are consistent.

Tests

• Adds test/ours/test-process-shim.js verifying the shim resolves the real process object (with nextTick) when given an ESM-default-shaped polyfill, and returns a plain process-like object unchanged.
• npm test, npm run lint, npm run test:format, and the browserify bundle test all pass.

Context

This fix is currently carried as a patch-package patch in Comunica to make it work in the browser; upstreaming it here removes the need for the patch. See comunica/comunica#1724.