feat: Add LiveQuery query operation

[Corvus400]

Issue

Closes #9086 and resumes #9864.

Approach

This adds one socket request for saved live query rows.

The server uses saved auth and selected fields.

Missing client or query data returns a clear error.

Tasks

Schema, server path, result messages, and tests are done.

Checks

Specs, lint, and build passed.

/claim #9086

[parse-github-assistant]

I will reformat the title to use the proper commit message syntax.

[parse-github-assistant]

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📝 Walkthrough

Walkthrough

This PR adds a websocket query operation: schema entry, server-side _handleQuery to execute stored subscriptions (with where and keys), client-side pushResult to emit op: 'result' messages, and tests covering success and error scenarios.

Changes

Live Query Query Operation

Layer / File(s)	Summary
Query Operation Schema Definition src/LiveQuery/RequestSchema.js	Request schema enum and operation definition updated to support op: 'query' with numeric requestId.
Client Result Publishing src/LiveQuery/Client.js, spec/Client.spec.js	Client.pushResult/_pushQueryResult serializes results (applying per-subscription field filtering via _toJSONWithFields), sends op: 'result' messages, and handles missing results as empty arrays. Tests verify payload structure, field selection, and empty results.
Server Query Execution and Dispatch src/LiveQuery/ParseLiveQueryServer.ts, spec/ParseLiveQueryQuery.spec.js	Server dispatch routes query to _handleQuery, which validates client/subscription, builds and runs a Parse.Query with stored class/where/keys and appropriate auth, then calls client.pushResult or Client.pushError; specs cover success, missing clientId, missing subscription, field filtering, and where-clause matching.

Sequence Diagram

sequenceDiagram
  participant Client as WebSocket Client
  participant Server as ParseLiveQueryServer
  participant DB as Parse.Query
  participant Response as Client.pushResult

  Client->>Server: {"op":"query","requestId":123}
  
  Server->>Server: Validate clientId exists
  Server->>Server: Lookup subscription by requestId
  
  Server->>DB: new Parse.Query(className)
  DB->>DB: Apply where clause
  DB->>DB: Apply field selection (keys)
  
  Server->>DB: find(sessionToken or useMasterKey)
  DB-->>Server: results array
  
  Server->>Response: pushResult(subscriptionId, results)
  Response->>Response: Map results via _toJSONWithFields
  Response-->>Client: {"op":"result","requestId":123,"results":[...]}

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 5 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Security Check	⚠️ Warning	The _handleQuery method does not invoke beforeSubscribe/beforeQuery triggers that may implement security checks, unlike _handleSubscribe.	Add beforeSubscribe trigger invocation to _handleQuery or create a beforeQuery trigger with equivalent security validation before query execution.

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The PR title 'feat: Add LiveQuery query operation' begins with the required 'feat:' prefix and clearly describes the main feature being added.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Engage In Review Feedback	✅ Passed	No review feedback comments are present on the PR. The PR status is "open" and ready for review; no reviewers have yet provided feedback requiring engagement or discussion.
Description check	✅ Passed	The PR description provides a clear issue reference, approach overview, and confirms tasks completion, though it lacks detailed documentation changes and security check information.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Corvus400]

This is ready for review.

This PR resumes #9864.

It keeps the server change focused.

The JS SDK side appears released in parse-community/Parse-SDK-JS#2114.

Local checks passed.

See the PR body for the commands.