Unity MCP Server error "Connection Revoked / No Pending Approval Found" is thrown when invoking an external MCP client tools

How to reproduce:

1. Create a new project
2. Install the AI Assistant package
3. Go to Project Settings > AI > Assistant MCP Extensions > Server Configuration > Config File > Open
4. Configure an external MCP client (e.g., Cursor) to connect with args: ["--mcp"] (See internal notes)
5. Go to Project Settings > AI > Unity MCP Server
6. Observe the client appearing in "Other Connections" and click "Approve"
7. Attempt to call any MCP tool from the external client
8. Observe the AI Assistant window

Actual result: AI Assistant throws a connection revoked error (see internal notes)
Expected result: The approved connection remains stable and the MCP tools are called

Reproducible with: 1.0.0-pre.2 (6000.3.15f1), 2.8.0-pre.1 (6000.3.15f1)

Reproducible on: Windows 11 x64, macOS Tahoe 26.1
Not reproducible on: No other environments tested

Workaround: In Project Settings > AI > Unity MCP Server, manually toggle the connection off and back on (re-enable it)

Notes:

• This suggests a state synchronization issue within Unity.AI.MCP.Editor.Bridge.CompletePendingApproval where the server fails to locate or validate the identity key that was just approved
• The workaround of re-enabling only persists for one tool call, indicating the approval state is not being stored/maintained correctly between requests