feat: cwriter for wasm v7

[Icemap]

No description provided.

[wanshicheng]

Your commits does not support GOOS=wasip1 and GOARCH=wasm

[Solaris-star]

This is a superset of #132 — it adds the same WASM stubs plus util_wasm.go for the ioctl constant. Two issues:

1. Build tags: uses the old //+build syntax. Go 1.17+ prefers //go:build. #132 already has the correct syntax — worth aligning.

2. IsTerminal returns true: same concern as #132 — WASM has no terminal, so false is more accurate. Callers checking IsTerminal to decide between TTY and plain output would get the wrong branch.

Recommend consolidating #132 and #133 into a single PR with //go:build tags and IsTerminal → false. The core approach (dummy Writer, no-op GetSize) is correct.

[Solaris-star]

I rechecked the current head b8e104015e35ebecc712cbf6cc585eee86cfd97e from a clean checkout.

There is a compile blocker for the target platform:

• go test ./... ✅ passed on the PR checkout (the default-platform cwriter package reports [no tests to run]).
• GOOS=js GOARCH=wasm go test ./cwriter ❌ fails at cwriter/writer.go:55: w.clearLines undefined.

Flush calls w.clearLines() whenever w.lines > 0; that method is supplied by writer_posix.go and writer_windows.go, both excluded by the new WASM build constraint. writer_wasm.go currently defines GetSize and IsTerminal but not the required (*Writer).clearLines method. Please add a WASM-safe no-op (or otherwise provide the platform implementation) and rerun the cross-compile test. I did not test browser/runtime behavior; this is a clean-checkout compile result at the SHA above.