🧹 Refactor MemoryDb::apply to improve readability

[undivisible]

🎯 What: The code health issue addressed
Refactored the highly complex and long MemoryDb::apply function in src/store/apply.rs. The logic has been broken down into two distinct helper functions: validate_apply_input for initial checks, and apply_commit for processing the individual commits within a transaction.

💡 Why: How this improves maintainability
The original function was difficult to read and maintain due to deep nesting and mixed concerns (validation, transaction management, and iteration over records). By splitting these responsibilities into descriptive helpers, the overall orchestrator becomes much clearer and simpler. This isolation makes testing and future modifications easier.

✅ Verification: How you confirmed the change is safe
Ran the entire test suite cargo test and cargo clippy --all-targets --all-features -- -D warnings. Verified there are no regressions.

✨ Result: The improvement achieved
A concise, highly readable apply function with well-encapsulated logic, preserving all existing behavior while enhancing maintainability.

---

PR created automatically by Jules for task 11080413117999858006 started by @undivisible

---

Note

Low Risk
Pure structural refactor of apply orchestration with identical validation and commit-processing logic; no API or data-path changes.

Overview
Improves readability of MemoryDb::apply by splitting its long, nested body into two helpers with no behavior change.

validate_apply_input now owns the upfront checks (scope, export/schema versions, ascending sequences, full commits, record scope). apply_commit owns per-commit pass processing, idempotent record apply/skip tracking, and commit append.

The main apply method is left as a short orchestrator: validate, open the transaction, apply each commit, record the operation, and commit.

^{Reviewed by Cursor Bugbot for commit 32bc881. Configure here.}

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[cursor]

Bugbot couldn't run - usage limit reached

Bugbot is counted against Cursor usage for this user or team, and this run hit a usage or spend limit.

A user or team admin can review and increase usage limits in the Cursor dashboard.

(requestId: serverGenReqId_f4847a42-4e8a-4f5f-998c-25f17d23ccfd)

[undivisible]

Superseded by the reviewed and merged integration in #22.

[google-labs-jules]

Superseded by the reviewed and merged integration in #22.

Understood. Acknowledging that this work is now obsolete and stopping work on this task.