Decoupling Global Operations: How pnpm Fixed Self-Upgrade's Manifest Entanglement

This patch resolves a usability issue where pnpm's self-upgrade command would fail when run outside project directories, incorrectly inheriting project manifest requirements. The fix introduces precise boundary conditions that distinguish between missing project context and verification failures within projects, ensuring global commands maintain proper autonomy. This architectural refinement demonstrates how careful ownership boundaries in command routing directly improve package manager reliability.