[blazor] Diagnostic traces - OTEL names review

[pavelsavara]

• rename RouteChange ->Navigate
• don't propagate HTTP/SignalR links to event traces
• rename internal methods to match above

Fixes #62556

[Copilot]

Pull Request Overview

This PR standardizes OTEL activity names and method signatures for Blazor diagnostic tracing by renaming “RouteChange” to “Navigate”, updating internal method names to match, and adjusting how HTTP/SignalR links are handled in circuit traces.

• Renamed navigation-related constants and methods from Route→Navigate and event methods to HandleEvent.
• Changed CircuitActivitySource to directly add HTTP/SignalR links to activities instead of storing them.
• Updated callsites in tests, Router, and Renderer to use the new method names.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Components/Server/test/Circuits/CircuitActivitySourceTest.cs	Adjusted test expectations for link propagation on circuit start
src/Components/Server/src/Circuits/CircuitActivitySource.cs	Switched from storing HTTP/SignalR contexts to adding links
src/Components/Components/test/ComponentsActivitySourceTest.cs	Renamed route and event activity start/stop methods
src/Components/Components/src/Routing/Router.cs	Updated navigation activity stop calls
src/Components/Components/src/RenderTree/Renderer.cs	Updated event activity start/stop calls
src/Components/Components/src/ComponentsActivitySource.cs	Renamed constants and methods for navigation and events

Comments suppressed due to low confidence (1)

src/Components/Components/test/ComponentsActivitySourceTest.cs:103

• In the event activity success test, you should call StopHandleEventActivity(...) instead of StopNavigateActivity(...) to correctly stop the event trace.

        componentsActivitySource.StopNavigateActivity(activityHandle, null);