feat(engine): Baileys engine — minimal slice (link + text send/receive)

.env.example

@@ -73,6 +73,11 @@ PUPPETEER_ARGS=--no-sandbox,--disable-setuid-sandbox,--disable-dev-shm-usage,--d
 # 2.3000.1023204257 is confirmed to reach "ready" (incl. ARM64 / Raspberry Pi 5) — uncomment it:
 # WWEBJS_WEB_VERSION=2.3000.1023204257
 
+# Baileys engine (used when ENGINE_TYPE=baileys). WebSocket client, no Chromium.
+# NOTE: the Baileys engine dependency is ESM-only; OpenWA therefore requires Node >= 20.19 (require-of-ESM support).
+BAILEYS_AUTH_DIR=./data/baileys
+# NOTE: proxy (PROXY_URL/PROXY_TYPE) is not yet supported by the baileys engine; it is ignored.
+
 # Humanise single sends: show a "typing…" indicator and pause briefly (length-scaled, jittered)
 # before each text send so messages don't look instantaneous (anti-ban). ON by default — set to
 # false to disable. SIMULATE_TYPING_MAX_MS caps the pause (default 5000). Does not affect bulk

CHANGELOG.md

@@ -27,9 +27,11 @@ plugins instead of in core (#265).
   documented as out of scope for now). (#294)
 - **`auto-reply` reference extension plugin**, first-party and **registered disabled by default** — enable
   it via `POST /plugins/auto-reply/enable` to exercise the capability layer end-to-end. (#294)
+- **Baileys engine (minimal slice)** — `ENGINE_TYPE=baileys` now selects a second, browser-free WhatsApp engine built on `@whiskeysockets/baileys` (WebSocket/Noise protocol, no Chromium). This first slice supports linking (QR + pairing code), sending and receiving **text**, recipient resolution, and typing presence; all other operations return HTTP 501 until later slices add a message store. Config: `BAILEYS_AUTH_DIR` (default `./data/baileys`). Proxy is not yet supported on this engine. (#299)
 
 ### Changed
 
+- ⚠️ **Node.js ≥ 20.19 now required.** The Baileys engine dependency (`@whiskeysockets/baileys`) is ESM-only and is loaded at startup, so OpenWA now requires Node ≥ 20.19 (for `require()` of ESM). Operators on older Node must upgrade. (#299)
 - Engine config is now **opaque per-engine**: `EngineFactory` passes only engine-neutral fields
   (`sessionId`/`proxyUrl`/`proxyType`) to an engine plugin and supplies engine-specific config (Puppeteer
   for whatsapp-web.js) as a blob via the plugin context, so a non-browser engine can be added without the