Privacy and size controls for large/sensitive file inventories

[toddysm]

Part of #168 (gap analysis: privacy/size). Depends on the inventory work (layers/packages/files).

Problem

#168 requires privacy and size controls for potentially sensitive or very large file inventories; none exist yet.

Scope

• Define and implement size/privacy controls (e.g. bounds, redaction, opt-out) for file/package inventories.

Acceptance criteria

• Configurable size/privacy controls with sane defaults.
• Tests + docs updated.