fix(deps): admit Sandbox 0.56 in Runtime's peer range

[drewstone]

Problem

The next agent-dev-container release publishes @tangle-network/sandbox 0.56.1 (version PR agent-dev-container#8350).
Runtime's peer range stops at ^0.55.0, so a consumer that installs Sandbox 0.56 beside Runtime gets a peer conflict.

Change

• Add ^0.56.0 to the @tangle-network/sandbox peer range.
• Update the range statement in docs/canonical-api.md and the packed-package-test range assertions (0.56.0 admitted, 0.57.0 refused).
• Add a patch release note.

Sandbox 0.56.0 adds Hub line role policies (agent-dev-container#8218) and removes no API. Runtime calls no new 0.56 API.

Proof

• scripts/lib/packed-package-test.test.mjs: 21/21 passed locally.
• The packed compatibility cohort derives its Sandbox rows from npm, so it exercises 0.56.x once npm serves it.

🤖 Generated with Claude Code

[tangletools]

✅ Auto-approved PR — fc3bc69d

Blanket team auto-approval is intentional. The merge gates are CI and codex-p1.
No automated review runs on this PR. This approval rests on the rule above alone.

_{tangletools · auto-approval · reason: blanket_auto_approve · 2026-09-27T14:29:54Z}