Add volume name option to WithPersistentVolume APIs to support binding pre-existing volumes

Please add an option to the `WithPersistentVolume` APIs to specify a volume name when configuring persistent storage.

**Problem**

Current behavior appears focused on dynamic provisioning. In some environments, we need to bind to a pre-existing persistent volume already present in the cluster (for example: manually provisioned storage, migrations, or policy-constrained environments).

Without a way to set volume name, it’s hard to reliably target an existing volume and avoid dynamic allocation.

**Proposed change**

Add an overload or option on WithPersistentVolume APIs to allow setting a Kubernetes volume name (or equivalent binding field), so Aspire can request/use a pre-existing volume.

Example (illustrative):
C#

`.WithPersistentVolume(volumeName: "existing-shared-pv")`

Expected outcome

Bind Aspire resources to specific, already-provisioned volumes.
Better support for static provisioning and enterprise cluster constraints.
Improved migration/interoperability with existing Kubernetes storage setups.

Start by locating the WithPersistentVolume APIs and tracing how their volume configuration becomes a Kubernetes binding. Review the existing API shape and persistence-related tests before deciding between an overload and an option; done means a caller can target the named pre-existing volume while existing dynamic provisioning behavior remains supported.

Written by the indexing model from the issue text.