The fingerprint canaries' obfuscator shells out to a Node helper that
require()s javascript-obfuscator. Without this commit, a fresh
pip install decnet would land the .py modules but not the .js helper /
package.json, and there'd be no documented way to provision Node side.
* pyproject.toml - extend tool.setuptools.package-data to ship
canary/_obfuscate_helper.js, canary/fingerprint_payload.js, and
canary/package.json with the wheel.
* decnet/cli/canary.py - new "decnet canary-install-toolchain"
subcommand. Resolves decnet.canary.__file__'s dir, runs
npm install --omit=dev there, exits non-zero with a clear message
if npm is missing or install fails. Idempotent - safe to call
every API service start.
* deploy/decnet-api.service.j2 - non-fatal ExecStartPre that calls
the new subcommand. Leading '-' so a missing Node toolchain only
degrades fingerprint canaries (loud at mint time) without keeping
the API from booting.
* tests/canary/test_cli.py - registration smoke test, missing-npm
exit path, and a mocked-subprocess test asserting the right argv
and cwd land on npm.
Realism cultivator already has a broad except Exception around
cultivate() in scheduler.py:195-211, so a missing toolchain on a
host running the realism tick degrades to an inert noise file with
no extra plumbing.
