✨ Add uniqueItems to array schema validation

[chrisjsewell]

This PR adds support for the uniqueItems validation constraint to array schema fields, enabling validation that all elements in an array must be unique when this constraint is set to true.

Seea also: https://json-schema.org/understanding-json-schema/reference/array#uniqueItems

[Copilot]

Pull request overview

This PR adds support for the uniqueItems validation constraint to array schema fields, enabling validation that all elements in an array must be unique when this constraint is set to true.

Key Changes:

• Added uniqueItems boolean field to array schema type definitions
• Implemented test case verifying validation error when duplicate array items are present
• Updated documentation to describe the new uniqueItems constraint

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/schema/fixtures/extra_options.yml	Added test fixture with uniqueItems: true and duplicate array items
tests/schema/snapshots/test_schema.ambr	Added expected validation error snapshot for unique items constraint
sphinx_needs/schema/jsons/SchemasRootType.schema.json	Added uniqueItems field to array schema definition
sphinx_needs/schema/jsons/ExtraOptionMultiValueSchemaType.schema.json	Added uniqueItems field to multi-value array schema definition
sphinx_needs/schema/config.py	Added uniqueItems TypedDict field with documentation
docs/schema/index.rst	Documented the new uniqueItems constraint for array fields

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.15%. Comparing base (4e10030) to head (18e3699).
⚠️ Report is 217 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1610      +/-   ##
==========================================
+ Coverage   86.87%   88.15%   +1.27%     
==========================================
  Files          56       70      +14     
  Lines        6532     9701    +3169     
==========================================
+ Hits         5675     8552    +2877     
- Misses        857     1149     +292     

Flag	Coverage Δ
pytests	88.15% <100.00%> (+1.27%)	⬆️

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