Add EntryLinks support

[eeshadutta1408]

This PR implements full support for Dataplex EntryLinks (both top-level and schema column-inlined links) in the kcmd tool. It enables catalog curators to manage relationships (such as definition/glossary linkages or schema joins) locally in a structured format and synchronize them with the cloud catalog.

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Key Features

• Manifest & Alias Mapping: Added entryLinks configuration blocks to snapshot/publishing schemas in manifest.ts, supporting custom and global/system aliases (e.g. definition, schema-join).
• Dataplex API Integration: Extended dataplex.ts with Glossary and EntryLinks endpoints (lookupEntryLinks, createEntryLink, deleteEntryLink, listEntryLinks), with built-in CRM project ID/number normalization.
• Bi-directional Synchronization: Implemented paginated, cached pulling for entry group scopes and Symmetrical Reference Matching on pushing in sync.ts to prevent accidental link deletion or duplicate creation.

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EntryLink Examples

Below are examples of how entry links are serialized locally in an entry's YAML file:

1. Schema-Join Link

For undirected relationships containing aspect metadata, such as join keys and inference attributes:

links:
  schema-join:
    - target: myzh-test-project-1.froyotech_dataset.component
      id: bigquery.googleapis.com/projects/myzh-test-project-1/datasets/froyotech_dataset/tables/component
      schema-join:
        joins:
          - source:
               name: product
               fields:
                 - name
            target:
               name: component
               fields:
                 - name
            type: JOIN
            inferenceSource: QUERY_HISTORY
        userManaged: true
        job:
          runTime: 2026-02-27T13:24:32Z
          name: Dataplex Catalog Usage Signals

2. Glossary definition Link

For directional references mapped to glossary term path targets (resolved dynamically using display names):

links:
  definition:
    - target: dc-cuj-staging-playground.global.UtilityTest.UtilityTerm1
      id: projects/dc-cuj-staging-playground/locations/global/glossaries/pephjajda-c7c4b951-9c078501-4f35fa82/terms/imbaoooej-b14cc513-abdaf298-1b8843c2

[nikhilk]

Does this need to page through the list of entry links to retrieve them all similar to list?

[nikhilk]

This function is expected to be used only within the service wrapper, the idea being all responses returned from this client layer are 'fixed', and any downstream user of this client should not have to think about such details.

[nikhilk]

Couple of things -

1. Alias functionality would probably be better added in future alongside support for entry type and aspect type aliases. Being worked on in https://github.com/GoogleCloudPlatform/knowledge-catalog/pull/20/changes ...
2. Still looking ahead, but we should support all link types without having to list them all here. The set of link types to be retrieved or created/modified should depend on the types listed in catalog manifest snapshot and publishing configuration.