feat(jolt-verifier): Refactor Akita verifier packing ownership and public API boundaries

[sumchecker]

Summary

• Move Akita packing adapter ownership out of public jolt-akita and keep jolt-akita native-PCS-shaped.
• Narrow jolt-verifier Akita prover support behind explicit prover_support APIs while keeping root exports verifier-facing.
• Fix Stage 8 precommitted proof-count rejection order and add ownership/regression coverage.

Test plan

• cargo fmt -q
• cargo nextest run --release -p jolt-openings --cargo-quiet
• cargo nextest run --release -p jolt-akita --cargo-quiet
• cargo nextest run --release -p jolt-verifier --cargo-quiet --features akita,core-fixtures
• cargo nextest run --release -p jolt-verifier --cargo-quiet --features core-fixtures,zk
• cargo clippy -p jolt-akita -p jolt-verifier --features akita,core-fixtures -q --all-targets -- -D warnings
• cargo clippy -p jolt-verifier --features core-fixtures,zk -q --all-targets -- -D warnings

[github-actions]

Warning

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