Add Constraint.sources field

[tylerpayne]

By providing sources to the constraints, users can follow links to see why a constraint violation is not beneficial to downstream agents

[Copilot]

Pull Request Overview

This PR adds a sources field to the Constraint class to enable linking constraint violations to relevant documentation. Users can now follow links to understand why specific constraint violations are problematic for downstream agents.

Key changes:

• Added sources() method to base Constraint class returning list of source URLs
• Implemented source URLs for OpenAI and tool schema constraints
• Modified constraint violation reporting to display source links as numbered references

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/mcp_interviewer/constraints/base.py	Adds SourceUrl type alias and sources() method to Constraint base class
src/mcp_interviewer/constraints/openai.py	Implements sources() method for OpenAI-related constraints with documentation links
src/mcp_interviewer/constraints/tool_schema_flatness.py	Implements sources() method for tool schema flatness constraint
src/mcp_interviewer/reports/interviewer/constraint_violations.py	Updates constraint violation display to include numbered source links
mcp-interview.md	Updated test results showing constraint violations with source references
mcp-interview.json	Updated test data with source link formatting changes

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