EF migration bundle docs say WaitFor(db) waits for database health, but Docker Compose publish uses service_started

## Summary

The EF Core migration bundle documentation says that, when using `PublishAsMigrationBundle(publishContainer: true)`, `.WaitFor(db)` ensures the database is healthy before the migration container starts.

However, when publishing to Docker Compose, the generated compose file uses `depends_on.condition: service_started` for the database dependency, and the PostgreSQL service does not get a generated Docker Compose `healthcheck`. That means the migration container can start before PostgreSQL is ready to accept connections.

## Documentation involved

EF Core migrations docs:

https://aspire.dev/integrations/databases/efcore/migrations/

The documented pattern is:

```csharp
var db = builder.AddPostgres("pg").AddDatabase("appdb");
var api = builder.AddProject("api").WithReference(db);

var apiMigrations = api.AddEFMigrations("api-migrations")
.WithReference(db)
.WaitFor(db)
.PublishAsMigrationBundle(publishContainer: true);
```

The docs state that `.WithReference(db)` provides the connection string source, and `.WaitFor(db)` ensures the database is healthy before the migration container starts.

The Docker Compose reference maps `.WaitFor(db)` to `condition: service_started`:

https://aspire.dev/app-host/docker-compose-to-apphost-reference/#dependencies-and-ordering

## Repro

Use an AppHost shape like this:

```csharp
builder.AddDockerComposeEnvironment("compose");

var postgres = builder.AddPostgres("postgres");
var db = postgres.AddDatabase("appdb");

var api = builder.AddProject("api")
.WithReference(db);

api.AddEFMigrations("api-migrations")
.WithReference(db)
.WaitFor(db)
.PublishAsMigrationBundle(publishContainer: true)
.PublishAsDockerComposeService((_, service) => service.Restart = "no");
```

Then run:

```powershell
aspire publish --apphost path\to\AppHost.csproj --output-path .\aspire-output --non-interactive --nologo
```

## Actual result

The generated Docker Compose output uses `service_started` for the database dependency:

```yaml
api-migrations:
depends_on:
postgres:
condition: "service_started"
```

The generated `postgres` service does not include a Docker Compose `healthcheck`.

## Expected result

Given the EF migration bundle documentation, I expected one of these outcomes:

1. Docker Compose publish translates the database readiness requirement into a generated healthcheck plus `depends_on.condition: service_healthy`, at least for database integrations that already have built-in health checks in Aspire local orchestration.
2. Or the EF migration bundle documentation clarifies that Docker Compose publish only emits `service_started`, and users need to manually customize the Compose healthcheck and dependency condition if they need database readiness before a migration container starts.

## Workaround

For PostgreSQL, this can be worked around by explicitly adding a Compose healthcheck and overriding the migration service dependency:

```csharp
postgres.PublishAsDockerComposeService((_, service) => {
service.Healthcheck = new Healthcheck {
Test = ["CMD-SHELL", "pg_isready -U \"$$POSTGRES_USER\""]
};
});

apiMigrations.PublishAsDockerComposeService((_, service) => {
service.Restart = "no";
service.DependsOn["postgres"] = new ServiceDependency {
Condition = "service_healthy"
};
});
```

## Version info

Observed with:

- Aspire CLI: `13.4.5+73114e86c64aeb9f3f3c7da8e37df1ae4281b27e`
- `Aspire.Hosting.Docker`: `13.4.5`
- `Aspire.Hosting.PostgreSQL`: `13.4.5`
- `Aspire.Hosting.EntityFrameworkCore`: `13.4.5-preview.1.26316.12`
- .NET SDK: `11.0.100-preview.5.26302.115`

I searched existing issues for combinations of `PublishAsMigrationBundle`, `WaitFor`, `Docker Compose`, `service_started`, and `service_healthy`, and did not find a matching issue.

## Note

This issue body was drafted with assistance from OpenAI Codex and reviewed before submission.