fix(core): refactor account update to prevent race condition

[MicaiahReid]

• Introduced AccountUpdatePolicy enum to manage authoritative vs. cache hydration updates.
• Replaced direct calls to write_account_update with apply_account_update across multiple modules.
• Updated logic in SurfnetSvm to handle account updates based on the new policy, ensuring local state is preserved when appropriate.
• Enhanced tests to validate behavior of local vs. remote account updates, ensuring local writes are not overwritten by stale remote data.
• Removed deprecated write_multiple_account_updates method and consolidated account update logic for clarity and maintainability.

Thank you @Arrowana for identifying this bug! Replaces #738

[greptile-apps]

Greptile Summary

The PR separates authoritative local account mutations from conditional remote or database hydration, resolving fetched accounts under the SVM write lock so concurrent local writes win.

• Adds explicit account provenance and update policies.
• Rechecks single and batch remote results atomically before hydration.
• Keeps coupled mint and programdata dependencies aligned with the retained primary account.
• Refreshes returned coupled results from current local state.
• Migrates RPC, runloop, snapshot, and cheatcode paths to the consolidated update API.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains; the current code skips the entire fetched composite when its primary is already live and refreshes returned coupled dependencies from retained local state.

Important Files Changed

Filename	Overview
crates/core/src/surfnet/locker.rs	Resolves fetched single and batch accounts under one writer lock, preserves concurrent local writes, and reconstructs returned coupled dependencies from local state.
crates/core/src/surfnet/svm.rs	Introduces authoritative and conditional-hydration policies with component-level guards that prevent stale coupled dependencies from being applied.
crates/core/src/surfnet/mod.rs	Replaces the prior update flag and specialized result variants with explicit source provenance and a unified coupled-account representation.
crates/core/src/surfnet/surfnet_lite_svm.rs	Tags account results according to whether they came from LiteSVM or persistent storage while retaining local-first lookup behavior.
crates/core/src/surfnet/remote.rs	Marks upstream account results as remote and emits unified coupled mint or programdata results for conditional hydration.
crates/core/src/rpc/accounts_data.rs	Removes redundant post-read writes because account resolution now performs safe hydration before returning.
crates/core/src/runloops/mod.rs	Removes the second startup-hydration write now that remote fallback atomically resolves and applies fetched accounts.

_{Reviews (8): Last reviewed commit: "Merge branch 'main' into fix/race" | Re-trigger Greptile}

[cds-amal]

Nice fix! The policy enum reads like the row selector of a decision table: given a policy and the account's local state, each cell is the action taken. Writing that table out might be worth a few minutes; it would make a compact rustdoc for AccountUpdatePolicy, and it is a good stress test of the model.

Two things to consider while filling it in:

1. how coupled accounts (a token account's mint, a program's programdata
   account) are represented, since they arrive inside the same
   GetAccountResult as their primary but resolve against their own
   local state;
2. whether "present only in the DB" distinguishes a row written this
   session from one inherited from a previous run.

My attempts at those cells kept needing footnotes 😞 , which usually means I'm missing an input; curious what you get.