(core): `Names.uniqueResourceName` should support generating multiple unique names from the same construct

### Describe the feature

`Names.uniqueResourceName` should support generating multiple different unique names when called multiple times with the same construct.

### Use Case

When creating multiple child resources that require unique physical names, I need to call uniqueResourceName before the child constructs are initialized. Since I can only pass the parent construct (this), I get the same name for all resources.

```ts
// These all return the same name
const name1 = Names.uniqueResourceName(this);
const name2 = Names.uniqueResourceName(this);

new SomeResource(this, 'SomeResource1', {
name: name1, // Need a unique name here
});

new SomeResource(this, 'SomeResource2', {
name: name2, // Need a different unique name here
});
```

Currently I have to manually construct names like ${Stack.of(this).stackName}-${this.node.id}-ABC, which loses the hash-based uniqueness guarantee that uniqueResourceName provides.

### Proposed Solution

Add an optional string parameter to `UniqueResourceNameOptions` that differentiates the generated name. For example, include it in the hash calculation so that different input strings produce different unique names while keeping the output length consistent.

E.g.

```ts
const name1 = Names.uniqueResourceName(this, { discriminator: '1' });
const name2 = Names.uniqueResourceName(this, { discriminator: '2' });
```

To meet maxLength constraint, the additional string might only be used to caluclate the hash component.

### Other Information

A workaround is to create empty constructs just for name generation:

```ts
const parent1 = new Construct(this, 'Parent1');
const parent2 = new Construct(this, 'Parent2');
const name1 = Names.uniqueResourceName(parent1);
const name2 = Names.uniqueResourceName(parent2);
```

This works but adds unnecessary constructs to the tree.

Or, use Lazy to defer name resolution until after child constructs are initialized:

```ts
const resource1 = new SomeResource(this, 'Resource1', {
name: Lazy.string({ produce: () => Names.uniqueResourceName(resource1, { maxLength: 40 }) }),
});
```

This requires using Lazy for every resource and is verbose.

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### AWS CDK Library version (aws-cdk-lib)

2.233.0

### AWS CDK CLI version

2.1100.1

### Environment details (OS name and version, etc.)

n/a

Start at the Names.uniqueResourceName entry point and inspect UniqueResourceNameOptions to understand current name and hash generation. Define how a discriminator should produce distinct names while respecting maxLength, then add coverage showing repeated calls with different discriminators return distinct valid names.

Written by the indexing model from the issue text.