Improve event detail layout and stack diagnostics

[ejsmith]

Summary

• remove the excess top spacing from promoted event tabs and Session Events while preserving their actions
• show project and tag metadata in the Stack section using columns aligned with Event detail values
• add a low-prominence Stacking Information dialog to the Stack options menu

Why

Promoted tabs and Session Events reserved a full action row above their content, creating a large empty gap. Stack metadata was also split between the Stack and Event sections, while the diagnostic values used to group a stack were not available in the new UI.

Verification

• npm run validate
• npm run test:unit (21 test files, 295 tests)
• local Playwright reproduction confirmed promoted and Session Events gaps are 8 px
• local Playwright verification confirmed Event, Project, and first Tag values share the same horizontal position
• locally verified the Stack options menu and Stacking Information dialog

Breaking changes

None.

[ejsmith]

/preview

[github-actions]

Preview deployed

• App: https://dev-app.exceptionless.io
• Collector: https://dev-collector.exceptionless.io
• Commit: 99f2dead6cda
• Version: 8.6.3-preview.issue.event-detail-layout.0.23
• Workflow run: view logs

[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
Exceptionless.Insulation	23%	23%	205	❌
Exceptionless.Core	73%	65%	9497	➖
Exceptionless.AppHost	38%	40%	139	❌
Exceptionless.Web	84%	67%	6898	✔
Summary	76% (22510 / 29436)	65% (10335 / 15822)	16739	✔