Superseded: support dependency installs without .zpkg.toml

[ORESoftware]

Superseded by consolidated PR #10 (feat/den-567-manifestless-flags-completion).

The useful design from this draft—an in-memory consumer manifest, strict real-terminal consent, non-interactive bypass aliases, locked reinstall, and no .zpkg.toml writes—has been semantically incorporated there together with:

• the merged canonical flags2env revision from feat: certify Zed package and shell contracts ORESoftware/flags-2-env#6;
• fail-closed bundled startup;
• best-effort nearest/unique-nested language-root selection;
• both Bash and Zsh generated completion;
• actual terminal/help, shell registration/autoload, Docker, and local-registry GitHub Actions coverage.

Tracking continues in Linear DEN-567.

[linear-code]

DEN-567