feat(v1): add admin rotation

[dimin4241-svg]

Summary

Adds a direct, current-admin-authorized set_admin entrypoint for Tholos v1. Rotation takes effect immediately, emits AdminUpdated, and keeps the instance TTL alive. The public contract docs and generated TypeScript client are updated; bond and resolver economics are unchanged.

Closes #128

Test plan

• cargo fmt --check, cargo clippy --workspace --all-targets -- -D warnings, and cargo test pass locally (make check)
• CONTRACT.md updated for the new public function and event
• scripts/testnet-smoke.sh passed against a fresh testnet deployment built from this branch
• Manually rotated the fresh deployment, confirmed the old admin was rejected by set_paused, and confirmed the new admin was accepted
• Regenerated and built packages/tholos-sdk

[collinsezedike]

This branch also shows as conflicting with main right now, that'll need a rebase separately from the finding below.

[collinsezedike]

This is an irreversible one-step admin transfer with no acceptance step from new_admin. If old_admin calls this with a mistyped, unreachable, or otherwise uncontrolled address, the write happens immediately and permanently replaces the only admin key. Since set_paused, update_resolvers, set_bond_amount, and set_admin itself all gate on this single stored address with no recovery path, one bad call locks out every admin-only capability forever. A two-step transfer, propose_admin plus accept_admin requiring new_admin's own authorization, would let the new key confirm control before old_admin's authority is dropped.

[dimin4241-svg]

Implemented the safer two-step admin rotation and rebased onto current main in commits 862205c and 28dd4fb:

• propose_admin(new_admin) is authorized by the current admin and stores a pending proposal.
• accept_admin() requires the proposed admin's authorization before changing authority; the pending proposal is then cleared and AdminUpdated is emitted.
• Added regression coverage for rejected arbitrary/old-admin acceptance and post-rotation authority, plus updated the contract docs and regenerated TypeScript bindings.

cargo test -p tholos passes: 77 tests; cargo fmt --all -- --check and pnpm install --frozen-lockfile && pnpm build for packages/tholos-sdk also pass.

[collinsezedike]

@dimin4241-svg thank you for the contribution. This looks good, there is nothing to flag.