feat: protect authoritative accounts from overwrites

[bmuddha]

What changed

• Reinterpret persisted state-flag bit 1 as AUTHORITATIVE and remove the compressed-account builder API without changing the serialized account layout.
• Mark delegated and transient targets authoritative after successful MagicRoot finalization, then reject later MagicRoot mutations with PrivilegeEscalation.
• Preserve atomic create-with-actions by allowing PostFinalize only immediately after the matching successful Finalize at the same stack height and caller.
• Keep non-authoritative replacement, large-transaction replication, and slot-ordering coverage aligned with the new boundary.

Closes #35, closes #36

Impact

Finalized delegated and transient accounts can no longer be overwritten by a higher-slot replacement, including through builtin CPI callers. Read-only, placeholder, system, ephemeral, and closed targets are not automatically marked authoritative. Existing persisted bit 1 values are intentionally reinterpreted; no migration or wire-layout change is introduced.

Validation

• cargo test -p solana-account — passed
• cargo test -p solana-transaction-context — passed
• cargo test -p magic-root-program — passed
• cargo test -p magicblock-engine --test accounts — passed
• cargo test -p magicblock-engine --test security — passed
• cargo test --workspace — passed
• git diff --check — passed

Reviewer notes

The ordering-sensitive boundary is in MagicRoot target authorization: the authoritative flag is applied only after executable loading succeeds, and the PostFinalize exception matches the immediately preceding trace entry by program, target, stack height, and caller.

[bmuddha]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• feat: protect authoritative accounts from overwrites #37 👈 (View in Graphite)
• feat: add state replicator crate on top of the engine #25
• feat: adds top level engine crate for global orchestration #24
• feat: added internal built-in magic root program #23
• feat: implement transaction processor crate #22
• feat: implements keeper crate - state orchestrator #17
• feat: implement superblock based ledger crate #15
• feat: add optimized accountsdb crate #14
• feat: add nucleus engine crate #18
• feat: add svm crate #21
• feat: add program runtime crate #20
• feat: add transaction context crate #19
• feat: forked transaction-view for increased limits #33
• feat: add customized solana-account crate #13
• chore: import upstream Solana runtime crates #31
• master

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