feature: support link-based sharing for inherited roles

[MatrixAdventurer]

Summary

Support sharing a role / inherited memory space by link so it can be imported by another Memoria Cloud user or previewed/imported by a non-user.

Problem

If Memoria adds role-scoped inherited memory (for example writer, reviewer, github-ops), users will naturally want to share those roles with others.

Today there is no role-aware sharing model. The likely workarounds are awkward:

• copying raw memories manually
• exporting the whole user memory space
• duplicating role-specific memory into another account by hand

Requested capability

A user should be able to share a role by link, for example:

• with another Memoria Cloud user
• with someone who is not yet a Memoria user

Suggested first version

Start with a template / import model rather than full live collaborative editing.

That means a shared role link would allow:

• previewing the role metadata and/or selected memories
• importing the role into another account
• creating a local copy/fork based on the shared role

Example use cases

• share a writer role with someone else as a writing assistant template
• share a reviewer role across a team
• publish a role as a reusable best-practice memory pack

Why this matters

Role-based memory becomes much more useful if it can be reused and shared.

This would make Memoria better for:

• multi-agent collaboration
• reusable workflows
• community templates
• onboarding non-technical users into structured memory systems

Future expansion

A later version could support stronger collaboration modes such as:

• read-only shared roles
• read/write collaborative roles
• org/team visibility controls

But the first version can stay simple and focus on link-based role sharing + import.