feat(setup)!: require Node 22.12+ and drop Node 20 (#152)

better-sqlite3 stopped publishing prebuilt binaries for Node 20's ABI
(115) in 12.10.0 - upstream, not a mirror gap:

    12.8.0 / 12.9.0   115 127 131 137 141
    12.10.0+              127 137 141 147

`better-sqlite3: ^12.8.0` resolves well past that, so every Node 20
install 404'd on the CDN, fell through to the source build, and demanded
Python plus a C++ toolchain before the bot could start at all. package.json
went on claiming `^20.19.0` worked, and the README went on recommending
Node 20 as one of two blessed versions. It was not a supported
configuration in any meaningful sense - it was a trap.

So say so up front: engines, both setup scripts, and the Docker images now
require Node 22.12+ (or 24+, which still needs a source build for opus).
The version gate in setup.bat / setup.sh is kept byte-identical to the
engines range, as before.

Also copy scripts/lib/console-log.mjs into the production image. The
previous commit had check-native.mjs import it, and the Dockerfile copies
check-native.mjs in on its own for `docker exec ... npm start` - without
its dependency that preflight now dies with ERR_MODULE_NOT_FOUND.

BREAKING CHANGE: Node 20 is no longer supported. Node 22.12 LTS or newer
is required; setup refuses to run on anything older.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/docker/Dockerfile

@@ -4,7 +4,7 @@
 # ==========================================
 
 # --- Stage 1: Build backend + frontend ---
-FROM node:20-slim AS builder
+FROM node:22-slim AS builder
 
 # Install build tools for native modules (opus, better-sqlite3)
 RUN apt-get update && apt-get install -y --no-install-recommends \
@@ -30,7 +30,7 @@ RUN npm run build
 RUN rm -rf node_modules && npm ci --production && npm cache clean --force
 
 # --- Stage 2: Production image ---
-FROM node:20-slim
+FROM node:22-slim
 
 # Install system FFmpeg — the ffmpeg-static npm package bundles a pre-compiled
 # binary that can SIGSEGV inside Docker (incompatible glibc / missing libs).
@@ -51,6 +51,8 @@ COPY --from=builder /app/node_modules ./node_modules
 # goes through npm, but an interactive `docker exec ... npm start` would
 # otherwise die on a missing script rather than starting the bot.
 COPY --from=builder /app/scripts/check-native.mjs ./scripts/check-native.mjs
+# ...and the module it imports for crash-proof logging.
+COPY --from=builder /app/scripts/lib/console-log.mjs ./scripts/lib/console-log.mjs
 
 # Data directory for database, cookies, logs
 RUN mkdir -p /app/data