Migrate AI Agent Run form's hand-rolled tab bar to mj-tab-nav

The AI Agent Run form (`packages/Angular/Explorer/core-entity-forms/src/lib/custom/ai-agent-run/ai-agent-run.component.*`) uses a hand-rolled tab bar that predates `mj-tab-nav`. Per the "spot a hand-rolled primitive → file the two-step issue, don't expand your PR" convention, PR #3296 added its new Branches tab following the existing local pattern instead of migrating the bar.

Follow-up: migrate the form's tab bar (Timeline / Visualization / Analytics / Details / Branches) to `mj-tab-nav` from `@memberjunction/ng-ui-components`, preserving the lazy `*Loaded` boolean pattern per tab.

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Start with packages/Angular/Explorer/core-entity-forms/src/lib/custom/ai-agent-run/ai-agent-run.component.* and inspect the current Timeline, Visualization, Analytics, Details, and Branches tab implementation alongside the mj-tab-nav API from @memberjunction/ng-ui-components. The work is done when the form uses mj-tab-nav and each tab preserves its lazy *Loaded boolean behavior.

Written by the indexing model from the issue text.