fix: align allowed_docker_image_hashes consumers with new return shape

[barakeinav1]

Fixups for #3752 to pull in — consumers of allowed_docker_image_hashes that the return-shape change misses (targets your branch so you can merge it into the PR).

• Launcher localnet scripts (test-verify-and-upgrade.sh, test-hash-override.sh) parse the view with jq '.[] | select(. == $h)' — that compares each element to a hash string, which never matches now that elements are { image_hash, expiry_timestamp_seconds } objects, so they'd fail even when the hash is approved. Switched to select(.image_hash == $h).
• Docs return type: contract/README.md and securing-mpc-with-tee-design-doc.md still showed Vec<NodeImageHash>.

Not touched (flagging, your call): softer prose mentions in operator/design docs (running-an-mpc-node-in-tdx-external-guide.md, chain-gateway-design.md receiver type, the attestation-cli README "look in contract state" hint) — they reference the method but not its return shape directly. attestation-cli code itself is unaffected (takes hashes as CLI args).

[kevindeforth]

Thank you!

[claude]

PR title type suggestion: This PR changes only documentation and test scripts, so the type prefix should probably be docs: instead of fix:.

Suggested title: docs: align allowed_docker_image_hashes consumers with new return shape

[claude]

Pull request overview

Follow-up to #3752 that reshaped allowed_docker_image_hashes()'s return type from Vec<NodeImageHash> to Vec<AllowedMpcDockerImageHash> (adds expiry_timestamp_seconds). This PR fixes two consumers that were silently broken by the shape change and refreshes two doc snippets to match.

Changes:

• Update jq selectors in the two rust-launcher localnet scripts from select(. == \$h) to select(.image_hash == \$h) so the hash lookup actually matches against the new object elements.
• Update the return type in crates/contract/README.md and docs/securing-mpc-with-tee-design-doc.md to Vec<AllowedMpcDockerImageHash>; the README description also now notes the newest-first ordering (matches the entries.reverse() at crates/contract/src/lib.rs:2099).

Reviewed changes

Per-file summary

File	Description
crates/contract/README.md	Public method table row updated to new return type and adds newest-first note.
docs/securing-mpc-with-tee-design-doc.md	Design-doc contract signature updated to new return type.
localnet/tee/scripts/rust-launcher/test-hash-override.sh	jq selector now reads .image_hash field.
localnet/tee/scripts/rust-launcher/test-verify-and-upgrade.sh	Two jq selectors now read .image_hash field (approval precheck + post-vote verification).

Findings

Blocking: none.

Non-blocking:

• `docs/tee-context-design.md:10` — the design-doc struct still shows `pub allowed_docker_image_hashes: Vec`, whereas the corresponding runtime type at `crates/tee-context/src/types.rs:8` is `Vec`. Drift predates this PR, but since we're chasing feat(metrics): expose the TEE image-hash allowlist expiry metrics #3752 shape mismatches it would be a natural place to land the fix. Not blocking — flagging for a follow-up if you'd rather batch design-doc realignment separately.

✅ Approved