INT-03 S6c: flip default wasm target preview1 → component + native-preview2 cleanup

[hyperpolymath]

ADR-015 canonical S6c (per .machine_readable/6a2/META.a2ml): demote the legacy core-wasm + wasi_snapshot_preview1 stdout path to a legacy/opt-in target and make the WASI-0.2 component the default wasm output. Bundled with the optional native-preview2 cleanup: replace the on-demand preview1 shims emitted by S4a (clock), S4b (env/arg sizes), S5 (env_at/arg_at), S6b (sock_shutdown) with direct wasi:clocks / wasi:cli / wasi:sockets calls — only pays off once preview2 is the default, hence the bundling.

This is the one-way door that ADR-015 was escalated for. The migration has been reversible-in-progress through S6b (legacy preview1 path still default); S6c is when reversibility ends. Touch points:

• bin/main.ml: default target switches; legacy preview1 stays selectable under a flag (matches how S6a kept reactor consumers byte-unchanged additively).
• tools/componentize.sh: defaults --command; legacy reactor still callable.
• lib/codegen.ml: native-preview2 emission path behind the new default; current Wasi_runtime.create_*_import helpers retained for the legacy path.
• tests/componentize/: smoke now asserts wasi:cli/run exports by default; preview1-stdout smoke moves under a legacy guard.
• Doc-truthing: docs/specs/SETTLED-DECISIONS.adoc ADR-015 amendment marking S6c shipped; docs/TECH-DEBT.adoc INT-03 closure; docs/ECOSYSTEM.adoc table flip.

Must survive: the typedwasm.ownership multi-producer ABI (shared with hyperpolymath/ephapax) byte-equal on the component's embedded core module; ADR-015's hard non-negotiable.

Ledger: INT-03 (S1, substrate) final slice. Refs #180.

[hyperpolymath]

Wrap default flipped: tools/componentize.sh now defaults to --command; S3 tests/componentize/smoke.sh passes --reactor explicitly. Compiler still emits preview1 core wasm — native-preview2 import cleanup remains the one-way door and is not in this change.

Landed on wasi-485-closeout (main...feat/wasi-485-closeout). Index #175 closed.

[hyperpolymath]

PR opened: #757 (feat/wasi-485-closeout → main).

[hyperpolymath]

Partial: wrap default landed in #757 — tools/componentize.sh now defaults to --command; S3 smoke passes --reactor. Compiler still emits preview1 core wasm.

Leaving this issue open for the native-preview2 import cleanup (the one-way door).

[hyperpolymath]

Not in #758. Native-preview2 is still the ADR-015 one-way door: compiler still emits wasi_snapshot_preview1 core wasm; wrap default is already --command.

Doing the default-flip + native wasi:clocks/wasi:cli/wasi:sockets import rewrite here would violate the typedwasm.ownership byte-equal-on-embedded-core contract without wasm-tools + a compiler in this environment. Leaving open.

[hyperpolymath]

Not landing in the #56 remainder PR (#759).

S6c is still the ADR-015 one-way door: default wasm output flips to the WASI-0.2 component, with native-preview2 replacing the on-demand preview1 shims, while typedwasm.ownership must stay byte-equal on the embedded core module.

Blocked here: this environment has no ocaml / dune / wasm-tools, so we cannot compile and prove that byte-equal invariant. #757 already wrapped --command; the default-flip + native-preview2 cleanup remains this issue.