chore(deps): align eval and interface cohort

[drewstone]

Summary

• pin @tangle-network/agent-eval to 0.137.0 and @tangle-network/agent-interface to 0.39.0
• resolve the single compatible transitive cohort: Agent Eval 0.137.0 → Agent Core 0.4.28 → Agent Interface 0.39.0
• add a compile-time contract against the canonical Interface candidate type
• strengthen packed-package verification to reject stack overrides, mismatched transitive versions, or multiple installed Eval/Core/Interface copies

The current origin/main source APIs compile against this cohort without a source compatibility patch, so this PR does not invent a local adapter or duplicate type.

Scope

Exactly five files change: package.json, pnpm-lock.yaml, CHANGELOG.md, scripts/verify-package.mjs, and tests/contracts/agent-stack-cohort.ts.

No Discovery or Agent Runtime files change.

Verification

• pnpm lint — 203 files checked
• pnpm typecheck — source and public contracts passed
• AGENT_KNOWLEDGE_RUN_NETWORK_TESTS=1 pnpm test — 59 files passed, 2 skipped; 550 tests passed, 7 skipped
• pnpm build — 35 files emitted
• pnpm verify:package — Publint and package types passed; clean npm consumer installed one physical copy each of Eval 0.137.0, Core 0.4.28, and Interface 0.39.0; five exports, CLI, skill, and repack passed
• pnpm verify:official-optimizers — agent-eval-rpc==0.137.0; 2 integration tests passed
• independent Codex review — no actionable defects
• git merge-tree --write-tree origin/main HEAD — aa28c96f187de512b09803ee2cd29a29774388db