docs: add page for couchbase_query (CouchbaseQueryVectorStore) and refactor existing Couchbase docs

[ejscribner]

Overview

• Adds a new page illustrating usage for new CouchbaseQueryVectorStore (community[minor]: Create CouchbaseQueryVectorStore langchainjs#8333)
• Refactors existing page path to ensure distinction between couchbase_search and couchbase_query
• Adjusts some language for clarity

Type of change

Type: New documentation page

Related issues/PRs

• GitHub issue:
• Feature PR: community[minor]: Create CouchbaseQueryVectorStore langchainjs#8333

• Linear issue:
• Slack thread:

Checklist

• I have read the contributing guidelines
• I have tested my changes locally using docs dev
• All code examples have been tested and work correctly
• I have used root relative paths for internal links
• I have updated navigation in src/docs.json if needed
• I have gotten approval from the relevant reviewers

Additional notes

[Copilot]

Pull Request Overview

This PR adds documentation for the new CouchbaseQueryVectorStore implementation and refactors existing Couchbase vector store documentation to distinguish between two different approaches: the Query-based implementation (new, preferred) and the Search-based implementation (existing). The changes clarify that Couchbase now offers two methods for vector search using different services.

Key changes:

• Adds comprehensive documentation for CouchbaseQueryVectorStore including setup, usage, indexing options, and comparisons
• Renames existing Couchbase documentation to couchbase_search.mdx to reflect its use of the Search Service
• Updates navigation and card references to distinguish between "Couchbase Query" and "Couchbase Search"

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/oss/javascript/integrations/vectorstores/index.mdx	Updates card titles and links to distinguish between Query and Search implementations
src/oss/javascript/integrations/vectorstores/couchbase_search.mdx	Refines title and clarifies this implementation uses the Search Service
src/oss/javascript/integrations/vectorstores/couchbase_query.mdx	New comprehensive documentation page for the Query-based vector store implementation
src/oss/javascript/integrations/providers/all_providers.mdx	Updates provider cards to show both Query (recommended) and Search implementations

[Copilot]

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

[Copilot]

Lines 260 and 261 both describe the same distance metric (Euclidean distance). Having both L2 and EUCLIDEAN listed separately with the same description is confusing for users. Please clarify if these are truly identical or if there are subtle implementation differences that should be documented.

Suggested change

	- `DistanceStrategy.L2` - L2 (Euclidean) distance
	- `DistanceStrategy.EUCLIDEAN` - Euclidean distance
	- `DistanceStrategy.L2`/`DistanceStrategy.EUCLIDEAN` - Euclidean (L2) distance

[Copilot]

Similar to the previous issue, L2_SQUARED and EUCLIDEAN_SQUARED appear to be redundant entries describing the same metric. Consider consolidating these or explicitly documenting any differences between the two strategies.

Suggested change

	- `DistanceStrategy.L2_SQUARED` - Squared L2 distance
	- `DistanceStrategy.EUCLIDEAN_SQUARED` - Squared Euclidean distance
	- `DistanceStrategy.L2_SQUARED` - Squared L2 (Euclidean) distance