feat(bundle): bundle the bit cli with esbuild

[GiladShoham]

Bundles the CLI into a single 60 MB CJS file plus 10 externals that cannot be inlined, with a generated shim package per core aspect re-exporting its slice of the bundle. npm run bundle builds it; --sea also builds a node single executable.

1.2 GB / 141k files → 160 MB / ~2.8k files. bit --help ~0.53s warm.

The shims emit the same dist/*.aspect.js and dist/*.main.runtime.js filenames the aspect loader already discovers, so the runtime needed no changes. The one source fix is real and independent of bundling: hook-require patched module.constructor.prototype.require, which under any bundler installs an enumerable require on Object.prototype.

bit start now works too: it serves the pre-built UI/preview bundles instead of running a bundler at all (shouldServeBundleUi/writePreviewEntry hash-match and serve from the shipped artifacts/, no public/ written). Verified end to end from a fresh bit init + bit create workspace: UI shell, workspace/scope roots, and the component's own preview all served from the pre-bundle. @rspack/dev-server and, as of this PR, @rspack/core itself (42 MB — was the single biggest external) are both fully excluded from the default build's package.json/node_modules, not just externalized — neither is reachable once bit start serves the pre-bundle instead of rebuilding.

Current size breakdown (measured on the real published-package shape, inPlace: true):

piece	size
bit.app.js (the bundle)	60.18 MB
UI/preview pre-bundle (artifacts/, shipped inside the shims)	16.7 MB — UI 16 MB (single rspack compilation, both roots share one copy — was 82.7 MB as two separate builds) + preview 0.7 MB
other 105 shims + locators + TS lib files	~16 MB
externals installed (node_modules)	64 MB — largest: typescript 23 MB, @pnpm 22 MB
total shipped distribution	160 MB (2,839 files)

The UI pre-bundle shrink (82.7 MB → 16.7 MB) comes from upstream #10628 (SSR fix + minifier, 58→24 MB) and #10629 (single rspack compilation shared by both UI roots instead of two separate builds, 24→16 MB), both now merged into this branch, plus #10631's bit start sanity e2e.

esbuild's own metafile.json (8.9 MB of build-analysis JSON, never read at runtime) is no longer written into the published package — still produced for local npm run bundle iteration and CI's diagnostic capture.

Producing the UI/preview pre-bundle locally needs a real bit build --tasks BundleUI,PreBundlePreview; it's now cached under a gitignored .bundle-cache/ (with a commit-hash + date meta.json) so node_modules wipes don't force re-deriving it every time.

Verified from an isolated dir: 40+ commands including create, status, tag, export, import, watch, server, start, and build --unmodified (all 9 tasks, rspack included).

npm run e2e-test:bundle / :sea run the suite against the artifact; CircleCI builds it once in setup_esbuild_bundle and shares it across the e2e nodes (gated to ^bit-bundle.* branches).

Full architecture, measurements, externals breakdown, script-vs-SEA analysis, the publishable package layout and open questions are in bundle-plan.md.

Draft: based on remove-core-envs-from-manifest, so the diff includes that branch. Opened to get CircleCI running.