[FEATURE]: Interactive GitHub Teams & Membership Graph Explorer

### Feature and its Use Cases

### What is the feature?
A new `"Teams Explorer"` dashboard inside OrgExplorer that fetches team data from the GitHub API and renders an interactive relationship graph. This graph maps Team parent nodes to their respective member contributors (avatars) and assigned code repositories. Additionally, users with admin PATs can drag and drop developer nodes into teams to update memberships visually.

### How would users benefit from it?
Auditing Permission Models: Mentors and org administrators can quickly see which contributors belong to which write/triage/admin teams across different repositories.
Visual Team Management: Simplifies managing permissions. Instead of digging through multiple submenus in GitHub's organization settings page, admins can perform drag-and-drop actions in a unified graph dashboard.
Onboarding Awareness: New GSoC students or contributors can visually explore the organization structure and identify who belongs to the frontend, backend, or documentation sub-teams.
What scenarios would this feature address?
Organizing GSoC students into sub-groups during coding periods.
Auditing repository access rights across nested organization teams.
Analyzing team collaboration density.

### Additional Context

**Proposed Implementation Outline:**
**API Services:**
Retrieve org teams via `GET /orgs/{org}/teams`.
Query team members via `GET /orgs/{org}/teams/{team_slug}/members`.
Mutate membership allocations using `PUT /orgs/{org}/teams/{team_slug}/memberships/{username}`.

**Visualization:**
Extend D3 or the existing canvas force-graph model (similar to NetworkPage) to represent Teams and member orbits.
Support HTML5 pointer event drops to trigger memberships updates.

**Addresses the open item outlined in**

`FeatureWishlist.md`

### Code of Conduct

- [x] I have joined the [Discord server](https://discord.gg/hjUhu33uAn) and will post updates there
- [x] I have searched existing issues to avoid duplicates

I would like to work on this issue !

Start by reading FeatureWishlist.md and the existing NetworkPage force-graph implementation, then trace the GitHub API integration for the listed team and membership endpoints. Done means a Teams Explorer dashboard renders teams, members, and repositories, with admin PAT users able to update memberships through the described drag-and-drop workflow.

索引モデルが issue の本文から書いたものです。