chore(release): tinycloud-node 1.16.1 (TC-500)

[samgbafa]

Summary

• bump tinycloud-node from the existing immutable v1.16.0 release to patch release 1.16.1
• document the merged TC-500/PR feat(TC-498): authorize exact native share email delivery #229 replay and idempotency correction: embedded Policy v3 delivery admission, canonical sealed invitation binding, deterministic signed receipts, and exact nonce/request-body/sender-DID replay protection
• preserve the ordinary /delegate then /invoke storage-enforcer data path with no Share-specific data plane
• synchronize the two tracked lockfiles with the crate version, matching the previous release precedent and the standalone M1 --locked CI gate

Refs TC-500. Based on current main merge 4a441adb33a92c89dcaf64368a93961f775df709.

PR #182 is obsolete release-plz output for the already-published 1.16.0 release and must not be merged.

Verification

• release/image version guard equivalent: PASS (1.16.1, previous immutable tag v1.16.0)
• root and standalone M1 cargo metadata --locked: PASS
• cargo fmt --all -- --check: PASS
• node scripts/check-deployment-policy-probes.mjs: PASS
• cargo test --locked -p tinycloud-node policy_v2_admits_v3_account_and_v4_accountless_receivers -- --nocapture: PASS
• git diff --check: PASS

Release boundary

Preparation only. Do not merge without explicit release authority: merging this PR allows release-plz to create v1.16.1, which triggers downstream release/image automation. No tag, GitHub Release, image publication, Phala deployment, or stale release PR merge was performed here.