Detach methods when disconnection confirmed.

[ilonatommy]

When a Blazor Server client loses connection, DefaultReconnectionHandler calls CircuitManager.reconnect(). If ConnectCircuit fails (circuit expired), it falls back to resume(), which creates a new RemoteRenderer on the server.
That renderer's constructor calls attachWebRendererInterop(1, newMethods) via JS interop. But reconnect() re-attached saved interop methods and didn't clean them up when ConnectCircuit returned false — causing:

"Interop methods are already registered for renderer 1"

The fix: CircuitManager.reconnect() calls detachWebRendererInterop when ConnectCircuit returns false.

The test exercises reconnect() on a CircuitManager with mocked internals to verify the fix, then confirms the server can register new interop methods.

Fixes #64738.

[Copilot]

Pull request overview

Fixes a Blazor Server reconnection edge-case where CircuitManager.reconnect() re-attaches renderer interop methods but (when ConnectCircuit is rejected) fails to clean them up, causing a subsequent resume() path to throw "Interop methods are already registered for renderer 1".

Changes:

• Detach web renderer interop methods when ConnectCircuit returns false during CircuitManager.reconnect().
• Add Jest coverage to reproduce the reconnect-then-resume double-registration scenario and validate the detach behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/Components/Web.JS/src/Platform/Circuits/CircuitManager.ts	Detaches renderer interop on ConnectCircuit rejection to avoid stale registration across reconnect/resume.
src/Components/Web.JS/test/WebRendererInteropMethods.test.ts	Adds regression tests covering the reconnect failure path and ensuring a new renderer can register interop methods after resume.

[oroztocil]

Maybe there could be a more fundamental fix for the broader workflow (that would avoid this in the first place) but I think this is a good low-risk fix for the problem that people run into in practice.

Let's merge it into P4 and after some time consider for servicing.

[ilonatommy]

/backport to release/10.0

[github-actions]

Started backporting to release/10.0 (link to workflow run)