Add ASP.NET Core PR attention canvas

[PureWeen]

Summary

• adds the project-scoped ASP.NET Core Team App canvas backed by the deterministic PR Attention skill in Add pull request attention queue skill #69040
• presents separate Review now and Needs rescue lanes, a compact Ready to merge strip, and expandable secondary classifications
• renders visible items by the engine-provided digestRank rather than deriving a second order in the UI
• supports an explicit digest-only author exclusion while preserving the full matched census
• validates the additive JSON contract while remaining compatible with earlier 1.0.0 producers
• adds read-only Open PR, Review, and Investigate rescue actions with opaque server-owned item IDs, stale-safe snapshots, and same-origin loopback protection

Screenshot

Validation

• node --test .github/extensions/aspnetcore-team-app/*.test.mjs passes all 23 tests
• extension reload and inspection reached === ready === with no provider errors
• live canvas opened with { "preset": "blazor", "excludeDigestAuthor": "PureWeen" }
• live query completed with query.complete: true across all 345 open PRs and 137 Blazor matches
• filter.excludeDigestAuthors retained PureWeen, and no PureWeen-authored PR consumed a visible digest position
• Review now rendered stable ranks across repeated summaries: Fix NullReferenceException when InputSelect (multiple) has no selection #66868, Fix InputBase retaining invalid parsing state and stale validation messages after Value change #67406, Fix null reference issue caused by validation exception when circuit is disposed #67146, Recover WebViewRenderer's unacknowledged batch queue from lost acknowledgements #68740, Throw clear error when invoking async JSInvokable method synchronously #68789
• Unescape relative path before file lookup to fix space-in-filename issue #62349 appeared in Needs rescue; [10.0] [Blazor] Support NavigateTo when enhanced nav is disabled (#52267) #64724 and Fix BL0012 false positive on await foreach and await using #68720 did not appear in Ready to merge
• runtime warnings were empty
• an independent final code review found no remaining significant issues

Stack

This PR is stacked on #69040. Its temporary base branch mirrors the current #69040 head at 259aaa46cb, so this remains a 13-file canvas-only diff. Review this after #69040 and retarget it to main after the base PR lands.