Unify WASM editor runtime with packaging/npm outputs (single source of truth)

[yeus]

WASM editor runtime paths are drifting between editors/wasm/* and pkg//*,
which causes fragile behavior and path mismatches.

Goal:
Make packaging/npm/build.mjs outputs the only runtime source of truth for the web
editor.

Scope:

• Editor runtime must load only from pkg/ artifacts produced by packaging/
  npm.
• Worker/module/wasm filenames must use canonical wasm-pack names
  (rumoca_bind_wasm.js, rumoca_bind_wasm_bg.wasm) everywhere.
• Remove/avoid parallel legacy runtime paths from editors/wasm artifacts.
• Keep one shared subdir-selection rule (release-full-web vs release-full-web-rayon)
  used consistently by editor + verify/smoke flows.

Acceptance criteria:

• One authoritative artifact path scheme: pkg//....
• No runtime imports that depend on editors/wasm/rumoca.js or editors/wasm/
  rumoca_bg.wasm.
• Local run (rum wasm edit) and CI smoke use the same artifact resolution logic.

[yeus]

I am not sure, but this might have been done with my latest wasm fix f81f159 but need to check before closing this here...