build(key-provider): switch to upstream repo and update deps

Switch from kvinwang fork to upstream MoeMahhouk/gramine-sealing-key-provider
(commit 180ff46). The fork was needed for the dcap-qvl 0.3.10 security fix,
which has since been merged upstream along with:
- Gramine v1.5 -> v1.9
- Rust toolchain -> 1.85
- Hardened attestation flow
- Removed sgx.enable_stats

Also regenerated Cargo.lock to fix bytes vulnerability (RUSTSEC-2025-0014).

Author: kvinwang