doctor reports the Portal test dependencies as ready on a machine with no npm

## What happens On a machine with Go but no Node, `./make doctor` prints all three of these: ``` [INFO] npm: not installed (needed for gui, Portal, Desktop, and the Markdown lint in ./make check docs) [OK] Portal test deps: installed (needed by ./make e2e) [OK] Playwright browsers: /Users/you/Library/Caches/ms-playwright ``` Reproduce it without uninstalling anything: ```bash env PATH="/usr/bin:/bin:$(dirname "$(which go)")" ./make doctor ``` Every line is true on its own. `optionalPortalBrowserTests` in `cmd/mk/doctor.go` checks the filesystem — `portal/node_modules/@playwright/test` and the Playwright cache — and neither depends on npm being on PATH. But read together they say the browser suite is ready on a machine that cannot run `npm ci`, `npm run`, or anything else the suite needs. doctor states facts without relating them, and this is the one place where two of those facts contradict each other in a way a reader will act on. ## What would help Make the two rows depend on the tool that would use them. A `[WARN]` naming the missing prerequisite, or a note that the check is moot without npm, both work — the point is that a contributor reading the block cannot come away believing `./make e2e local` will run. Keep them out of `doctor`'s failure count either way: they are optional paths, and doctor's exit code is about whether the core toolchain works. ## Verify ```bash ./make doctor # on your normal PATH env PATH="/usr/bin:/bin:$(dirname "$(which go)")" ./make doctor ./make test ./cmd/mk ``` `cmd/mk/doctor.go` is the only file involved. There is no test over doctor's output today, so adding one for this case would be welcome but is not required.