chore: sync fork with upstream (conflicts resolved)

[yosefAlsuhaibani]

Resolves the merge conflicts blocking the fork sync in #30 (which is ocaml:master → master and cannot be updated directly since its head is upstream's branch). This branch merges upstream/master into the fork with conflicts resolved.

Fork customizations preserved

• opam pinned to 2.5.0 (>=2.5.0 < 2.5.1) — see OPAM_STABLE_VERSION_RANGE in opam.ts. Upstream uses <2.6.0; flagging in case the pin is no longer needed.
• opam internal Cygwin with extra packages (--cygwin-extra-packages), now scoped to the cygwin windows-environment
• save-opam-post-run input + post-step opam cache save
• Alpine/apk support (DISTRO detection)
• Unconditional opam repository re-sync (even on cache hit)
• "v2" cache-key suffix and the cache-prefix input (upstream removed cache-prefix; kept since the fork still uses it)

Upstream changes adopted

• Vite Plus build replacing Turborepo/Biome/esbuild — dist/ is now *.mjs (regenerated)
• MSYS2 + MSVC Windows support (windows-environment, windows-compiler inputs)
• opam binary fallback (converges with the fork's "skip releases without binaries")
• Dependency and tooling updates

Validation

• yarn typecheck — passes (5 packages)
• yarn lint — 0 errors, 0 warnings, formatting clean
• yarn build — succeeds, dist/ regenerated and confirmed to embed all fork features

Once merged, #30 can be closed.

🤖 Generated with Claude Code

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Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ yosefAlsuhaibani
❌ smorimoto
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[yosefAlsuhaibani]

• feat: dune-cache on windows via vhdx #33
• feat(dune-cache): export DUNE_CACHE=enabled + no size limit #32
• chore: sync fork with upstream (conflicts resolved) #31 👈 (View in Graphite)
• master

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