Flag new dependency installs

Surfaces a new third-party dependency being added — npm/pnpm/yarn/bun, pip/pipx/poetry/uv, gem, cargo, go get, composer, bundle, dotnet and mix. Non-blocking. Each form requires a PACKAGE ARGUMENT, so a lockfile restore that adds nothing — npm ci, pnpm install, pnpm install --frozen-lockfile — is deliberately not flagged. A global flag between the tool and its subcommand is tolerated (npm --silent install pkg, pnpm -C apps/web add react). MISSES a package named after more than one flag between the subcommand and the package, an install run through a wrapper, a dependency added by hand-editing a manifest, and the system package managers (apt, brew, apk), which install machine software rather than project dependencies. A quoted MENTION is not a use: a search, a git commit -m message, an echo or a curl --data body that only names this command is left alone. That holds only while every shell metacharacter stays inside the quotes, so git commit -m "x" && … is still caught; and the carrier must be the first word, so sudo grep … is not exempt.