perf: port entity extraction NER to Rust→WASM for faster memory write path (@stackbilt/wasm-core)

[stackbilt-admin]

Problem

extractEntities() in web/src/kernel/memory/graph.ts runs 5 separate matchAll regex passes on every memory consolidation ADD/UPDATE operation:

// graph.ts ~line 48
const CAPITALIZED_PHRASE = /\b([A-Z][a-z]+(?:\s+[A-Z][a-z]+)+)\b/g;
const TECH_TERMS = /\b(OAuth\s*2\.?1?|MCP|D1|KV|...)\b/g;
const VERSION_REFS = /\b(v\d+\.\d+(?:\.\d+)?|Phase\s+\d+)\b/gi;
const HYPHENATED_NAMES = /\b([a-z]+-[a-z]+(?:-[a-z0-9]+)?)\b/gi;

// Called on every ADD/UPDATE:
for (const match of fact.matchAll(CAPITALIZED_PHRASE)) { ... }
for (const match of fact.matchAll(TECH_TERMS)) { ... }
for (const match of fact.matchAll(VERSION_REFS)) { ... }
for (const match of fact.matchAll(HYPHENATED_NAMES)) { ... }
// + word scan against KNOWN_PROJECTS/KNOWN_TOOLS/KNOWN_PEOPLE Sets

JS regex engines reinterpret pattern strings on each call. With consolidation running every cron cycle and up to 3 ADD/UPDATE ops per run (plus extractNodes() calling this per node upsert), this adds up across the memory write pipeline.

Proposal

Port extractEntities() to Rust→WASM as part of @stackbilt/wasm-core (Phase 2):

• Compile all 4 patterns once at WASM module init time using the Rust regex crate (which compiles to a DFA/NFA — significantly faster than repeated JS regex interpretation)
• Known entity sets (KNOWN_PROJECTS, KNOWN_TOOLS, KNOWN_PEOPLE) become Rust HashSet<&str> — O(1) lookup, no JS object overhead
• Single-pass extraction where possible (combine patterns into an alternation)
• Expose: extract_entities(fact: string) -> string[]

// proposed usage
import { extractEntities } from '@stackbilt/wasm-core';
const entities = extractEntities(fact);  // Rust compiled regex, single pass

Why this fits WASM:

• Pure string processing, no I/O
• Rust regex crate compiles patterns to automata at init — subsequent matches are state-machine transitions, not interpretation
• Known entity sets as static HashSet benefit from Rust's faster hashing (FxHashSet)
• Called frequently on the memory write hot path

Scope

• web/src/kernel/memory/graph.ts → extractEntities() function
• extractNodes() caller unchanged — just swaps the inner extraction call
• No schema or API surface changes

Note: Lower priority than spreading activation (Phase 1). File for tracking. Not a code change request.

References

• web/src/kernel/memory/graph.ts — extractEntities(), extractNodes()
• llm-providers#96 — Phase 0 (latency histogram)
• aegis-oss#N — Phase 1 (spreading activation, filed in same session)
• wiki: wasm-core-strategy-2026 (internal)