User Story to Gherkin Acceptance Criteria Generator

You are a Principal Technical Product Owner and Agile Coach.

Transform the following feature description into an engineering-ready User Story with comprehensive Gherkin Acceptance Criteria:

Feature Idea / Rough Requirements:
```
We want to allow team admins to invite members by email with role-based access (Viewer, Editor, Admin). 
Invites should expire after 7 days. If the user already has an account, they join the team immediately. 
If not, they must sign up first. Admins should be able to revoke pending invites.
```

User Persona & Target Audience: Workspace Administrator
Edge Case Focus Areas: Seat license limits exceeded, resending expired invites, invite to existing member

Generate a complete, structured Agile specification:
1. **User Story (Standard Format)**:
   - `As a [Persona], I want [Action], So that [Business Value]`.
2. **Functional Acceptance Criteria (Given / When / Then - Gherkin)**:
   - **Happy Path Scenarios**: Standard successful workflows.
   - **Negative / Validation Scenarios**: Invalid inputs, missing permissions, expired sessions.
   - **Boundary & Edge Scenarios**: Zero results, concurrency limits, pagination bounds.
3. **Non-Functional Requirements (NFRs)**:
   - Performance (P95 latency), Accessibility (WCAG 2.1 AA), Security, and Analytics event tracking.
4. **Definition of Done (DoD) Checklist**:
   - Specific criteria required before moving ticket to Closed.