Clarify intent-aware safe-output mutation contracts across optional and strict modes

[Copilot]

Intent-aware issue mutation tools were generating ambiguous contracts: omitted issue-intent exposed metadata but did not encourage it, while strict mode could require metadata in schema yet still describe it as optional. add_labels was especially inconsistent by enforcing object-only labels in strict mode while still documenting plain string labels.

• Mode-specific intent guidance

  • Omitted issue-intent now strongly encourages rationale and confidence for all intent-aware mutations while keeping both optional.
  • issue_intent: true now states clearly that rationale and confidence are required.
  • issue_intent: false continues to omit intent guidance and strip intent fields from generated schemas.

• Strict add_labels contract alignment

  • Replaced the contradictory strict-mode description with object-only guidance.
  • Explicitly documents per-label required fields: name, rationale, and confidence.
  • Uses metadata-rich label examples and removes strict-mode language implying plain strings are allowed.

• Field description cleanup

  • Strict-mode field descriptions for rationale and confidence no longer call those fields optional.
  • Optional-mode descriptions now consistently recommend metadata and enumerate allowed confidence values: LOW, MEDIUM, HIGH.

• Regression coverage

  • Added generator tests for all affected mutations covering:
    • optional guidance when issue-intent is omitted
    • required guidance and required-field wording in strict mode
    • disabled guidance/field stripping when issue-intent: false
    • strict add_labels object-only schema + matching description

Example strict add_labels output now matches both schema and description:

{
  "type": "add_labels",
  "item_number": 123,
  "labels": [
    {
      "name": "bug",
      "rationale": "The report describes reproducible incorrect behavior.",
      "confidence": "HIGH"
    }
  ]
}

• Fixes Intent-aware mutation descriptions should encourage optional metadata and clearly require strict metadata #46853

[Copilot]

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