fix(scraper): replace glibc binary with npm single-file-cli on node:22-alpine

The pre-compiled single-file binary requires glibc symbols (__res_init)
that Alpine's gcompat shim does not provide, causing exit status 127.
Switch runtime base to node:22-alpine and install single-file-cli via npm.
Also add .dockerignore to exclude bin/ and static/ from build context.

scraper/.dockerignore

@@ -0,0 +1,4 @@
+bin/
+static/
+*.md
+.git