Build invoice co-creator permission levels (view/edit/admin)

[Kingsman-99]

Description

CoCreatorPanel.tsx adds co-creators with presumably uniform permissions — there's no distinction between a co-creator who can just view vs one who can edit/manage. This issue adds permission levels.

Technical Context

Involves src/components/CoCreatorPanel.tsx. Add a permissionLevel: "view" | "edit" | "admin" per co-creator (stored alongside existing co-creator data, client-side enforced since the contract itself only tracks the co-creator address list). "View" can see but not modify; "edit" can modify invoice details pre-funding; "admin" can also manage other co-creators.

Acceptance Criteria

• Adding a co-creator requires selecting a permission level, defaulting to "view"
• UI actions (edit details, manage co-creators) are hidden/disabled based on the connected address's permission level
• Only "admin"-level co-creators (including the original creator) can change another co-creator's permission level
• Permission enforcement is clearly documented as client-side/UX-level, not a contract-level guarantee
• Unit tests: permission-gated action visibility for each level

---

[1sraeliteX]

Hello, I would like to work on this issue

[primexk5]

Assign this issue to me, Gm maintainer