Document authoritative Developer Info contract for tool-call evaluation

Context

M365-Copilot-Agent-Evals PR https://github.com/microsoft/M365-Copilot-Agent-Evals/pull/431 depends on an authoritative WorkIQ contract for application/vnd.ms-workiq.developer-info. The current developer-info.md is marked Proposal and not yet implemented.

Related Evals issues: https://github.com/microsoft/M365-Copilot-Agent-Evals/issues/224 and https://github.com/microsoft/M365-Copilot-Agent-Evals/issues/280.

Required contract

• Accepted media type and AgentCard/accepted_output_modes activation
• A2A message/send and message/stream accumulation semantics across artifact updates
• Append/replace/patch, ordering, deduplication, and conflict rules
• Terminal behavior proving Developer Info is complete for a turn
• Conversation/request/turn correlation invariants
• Canonical nested DeveloperInfo.plugins.executions[] structure
• Canonical tool naming, case sensitivity, uniqueness, and stability invariants
• tool_call_id, attempt identity, parent/logical-call identity, and retry correlation
• Which selected, attempted, failed, canceled, interrupted, and auth-required executions are emitted
• Authoritative successful/failed/indeterminate execution outcome algorithm

Acceptance criteria

1. Publish the finalized contract in the owned WorkIQ documentation.
2. Add conformance examples for single call, multiple calls, failed call, retry-success, and multi-frame streaming.
3. Identify the implementation/rollout status consumers can use to gate support.
4. Link the finalized document back to PR #431.

This issue is an approval dependency for PR #431, not an informal follow-up.

Start with the current developer-info.md and review PR #431, then consult related Evals issues #224 and #280. Done means the owned WorkIQ documentation contains the finalized contract, conformance examples for the listed call and streaming cases, consumer-facing implementation or rollout status, and a link back to PR #431.