[FEATURE] GAP-021: --scan-all-users multi-home inventory

[hello-args]

Summary

Enterprise fleet inventory across multiple user home directories (GAP-021).

Problem

GAP-021 is Missing (P1). Inventory only scans the current user home. Requires stronger privacy controls than #87.

Dependencies: Should not ship without #287 (optional consent) and redaction defaults (#288 / #289 patterns).

Expected Behavior

--scan-all-users (or policy-driven equivalent) with:

• Explicit consent gate (see [SECURITY] Optional consent gate for mcts inventory auto-discovery #287)
• --redact-paths on by default for fleet output
• Audit logging guidance for enterprise

References

• GAP-021 — feature expansion plan
• [SECURITY] mcts inventory reads local MCP configs without consent gate #87 — single-user privacy controls
• [SECURITY] Optional consent gate for mcts inventory auto-discovery #287 — consent gate

Acceptance Criteria

• Multi-home discovery behind explicit flag + consent
• Redaction on by default for fleet output
• Enterprise docs + tests