Complete fix: Deserialize observable query response data for all transfer modes (#2173)

[einari]

Fixed

• Observable query response data is now properly deserialized for all transfer modes, fixing Guid fields and other strongly-typed fields losing their methods (guid.equals is not a function #2173)

Summary

The initial fix (PR #2176) only addressed delta mode changeSet deserialization, but the root cause affects all observable query responses, not just delta updates.

The Problem

When observable query responses arrive from the server, the data is transmitted as plain JSON objects. The code was never deserializing this data into model instances with their @field decorators applied. This caused:

• Guid fields to lose their .equals() method
• DateTime fields to be plain strings instead of Date instances
• Other strongly-typed fields to lack their methods
• Downstream components (like ChecklistValidation) to crash when calling methods

Root Cause

The issue exists in ALL response paths:

1. Initial response with full data array — QueryResultWithState.fromQueryResult() just passes data through without deserializing
2. Subsequent full-data responses (non-delta mode) — Same issue
3. Delta mode with changeSet items — The changeSet items were deserialized in PR Fix Guid field deserialization in observable query delta reconstruction (#2173) #2176, but...
4. Delta mode fallback (no previous result) — Falls back to un-deserialized data

The Fix

Added deserializeResponseData() function that:

• Checks if data is an array and modelType is available
• Calls JsonSerializer.deserializeArrayFromInstance() to instantiate all items with proper types
• Covers all response paths in the subscription callback

Now all response data, regardless of transfer mode, is properly instantiated with @field decorators applied and methods available.

Testing

• Existing regression test from PR Fix Guid field deserialization in observable query delta reconstruction (#2173) #2176 still passes
• All adjacent observable query tests pass
• Full Release build succeeds without warnings