ERD entity details "Open" button in the Admin app does nothing (Interaction output has no subscriber)

## What happens

In the **Admin app → Data & Schema → ERD**, selecting an entity opens the details panel on the right (e.g. *Certifications*). The panel has an **Open** button in its header. Clicking it does nothing — no navigation, no tab, no error in the console.

Screenshot context: `mj.morecheese.org/app/admin/Data%20&%20Schema?section=erd`, Certifications entity selected, "Open" button top-right of the details panel.

## Why

The click does fire, but it dead-ends two hops up:

1. The ERD details panel emits `openEntity`, and `mj-erd-composite` forwards it as `entityOpened` (`packages/Angular/Generic/entity-relationship-diagram/src/lib/components/erd-composite/erd-composite.component.ts`).
2. `EntityAdminDashboardComponent.onEntityOpened()` handles that by emitting the generic `BaseDashboard.Interaction` output with `{ type: 'openEntity', entity, data }` (`packages/Angular/Explorer/dashboards/src/EntityAdmin/entity-admin-dashboard.component.ts` ~L122–140).
3. **Nothing subscribes to `Interaction`.** A repo-wide search finds no `(Interaction)` binding and no `.Interaction.subscribe` anywhere in Explorer.

Both hosts of this dashboard miss it:

- `BaseAdminContainerComponent` (`packages/Angular/Explorer/dashboards/src/Admin/base-admin-container.component.ts` ~L247) creates the dashboard dynamically and subscribes only to `Error`. It subscribes to neither `Interaction` nor `OpenEntityRecord`, so even the ERD's *record* opens (`onOpenRecord` → `OpenEntityRecord`) are dropped inside the Admin app.
- `DashboardResourceComponent` (`explorer-core/.../dashboard-resource.component.ts` ~L738, ~L847) subscribes to `OpenEntityRecord` but also not to `Interaction`, so the Open button is equally dead when the dashboard is opened as a workspace resource.

## Expected

Open should open the entity's own record (**MJ: Entities**, PK = `entity.ID`) in Explorer — the same thing the ERD's record-open path and the sibling dashboards (Data Explorer, Theme Studio) do via `OpenEntityRecord`.

## Suggested fix

1. In `EntityAdminDashboardComponent.openEntity()`, stop emitting the orphan `Interaction` and emit `OpenEntityRecord` instead:
```ts
this.OpenEntityRecord.emit({
EntityName: 'MJ: Entities',
RecordPKey: CompositeKey.FromID(entity.ID), // or FromURLSegment against the Entities metadata
});
```
2. In `BaseAdminContainerComponent`, subscribe to the hosted dashboard's `OpenEntityRecord` and route it the same way `DashboardResourceComponent` does (NavigationService / `OpenEntityRecord` re-emit up to the app shell). That also fixes record opens from the ERD canvas inside Admin, which are silently dropped today.
3. Consider removing the unused `BaseDashboard.Interaction` output (typed `EventEmitter`), or documenting what is supposed to consume it — right now it is a trap for exactly this kind of bug.

## Repro

1. Admin app → Data & Schema → ERD.
2. Click any entity node → details panel opens.
3. Click **Open** in the panel header.
4. Nothing happens.

Observed on `next` @ c1fea88930.

Start with EntityAdminDashboardComponent.onEntityOpened() and openEntity() in packages/Angular/Explorer/dashboards/src/EntityAdmin/entity-admin-dashboard.component.ts, then trace the hosted-dashboard subscriptions in BaseAdminContainerComponent and explorer-core/.../dashboard-resource.component.ts. Reproduce the ERD workflow and compare it with the existing OpenEntityRecord handling; done means the entity Open button and ERD record opens navigate to the entity record in both hosts.

Written by the indexing model from the issue text.