What kind of change does this PR introduce?

feat

What is the new behavior?

• Consumers can choose Splat.ApplicationInsights for the Application Insights v2 SDK or Splat.ApplicationInsightsV3 for the Application Insights v3 SDK.
• Existing consumers keep native page-view telemetry by staying on Splat.ApplicationInsights; that package remains on the v2 SDK.
• New v3 consumers reference Splat.ApplicationInsightsV3 and use the v3-prefixed namespace:

using Splat.ApplicationInsightsV3;

• ApplicationInsightsViewTracking in the v3 package records view navigation as custom events named PageView with the view name in the Name property.
• ApplicationInsightsFeatureUsageTrackingSession is available in the v3 package for feature start/end events and exception tracking through the existing Splat APM contracts.

What is the current behavior?

• Splat.ApplicationInsights is the only Application Insights package and is pinned to the v2 SDK.
• Moving that package directly to v3 would remove native TrackPageView support from consumers because Application Insights v3 removed that API.
• Related to chore (deps): Update Microsoft.ApplicationInsights to v3 #1505.

What might this PR break?

None. The v3 support is opt-in through a new package, and the existing v2 package remains unchanged.

Checklist

• I have read the Contribute guide
• Tests have been added or updated (for bug fixes / features)
• Docs have been added or updated (for bug fixes / features)
• Changes target the main branch
• PR title follows Conventional Commits

Additional information

• Splat.ApplicationInsightsV3 uses Microsoft.ApplicationInsights 3.1.2.
• OpenTelemetry.Api is pinned to 1.17.0 to avoid vulnerable transitive versions from the v3 SDK dependency graph.
• The v3 public API entries are in shipped baselines for all target frameworks.
• Verified locally with dotnet build Splat.slnx -c Release, dotnet test --solution Splat.slnx -c Release, and the v3 test project after moving the new APIs to shipped.