fix: skip node preflight gates whose npm script is missing; parse node:test counts

Missing npm script → skip, not fail.
Applies to tests and build gates that fall back to the profile, when the command is npm run <script>, npm run-script <script> or npm test and package.json has no such script.
The gate is listed in gates_unrun, so it can't read as a pass it didn't earn.
Unchanged:
commands wired under [gates];
a script that exists still runs and can fail;
an unreadable package.json runs the command as before.
Node baseline test count.
The regex only matched mocha's N passing. It now also matches ℹ tests N and # tests N (node:test, spec reporter and TAP) and Tests: N passed (jest, vitest).
Preflight takes whichever alternation group matched.
This applies to new inits. An existing profile.lock.toml keeps its old regex.