JS WAM: op/3 dynamic Pratt operator table

[s243a]

G-W2 follow-up: the JS WAM Pratt reader now consults a live operator table so op/3 (and compile-time :- op/3 via javascript_wam_ops/1) can add or override ISO defaults.

What landed

• Infix xfx / xfy / yfx, prefix fx / fy, postfix xf / yf
• Priority 0 removes that specifier; name may be an atom or a list of atoms
• ISO: infix and postfix of the same name cannot coexist; prefix may share a name with infix
• Emit-time seed: javascript_wam_ops([op(P,T,N), ...]) (alias js_op_decls/1) → Runtime.install_declared_ops

Tests

• probe_op3/0: custom infix + prefix + postfix + list-of-names, parsed with read_term_from_atom/2, matching SWI
• emitted_op_decls: compile-time javascript_wam_ops([op(700, xfx, likes)]) without a runtime op/3 call

Branched from grok/wamjs-term-meta and extended it (net additions). No INTEGRATION_PATCH.md (no shared files).

Residuals

• current_op/3 not implemented
• Ops are process-global (like SWI), not module-local