Handle concurrent order taking: refactor PerOrderIdMutex, move it to util/index.ts for more clean reusability [1/2]

[Luquitasjeffrey]

Summary by CodeRabbit

• Chores
  • Internal code reorganization to centralize utility functions and improve maintainability.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: cb70f928-263c-417a-a056-991a2ff5f6af

📥 Commits

Reviewing files that changed from the base of the PR and between e838c79 and 04aacc1.

📒 Files selected for processing (4)

• jobs/cancel_orders.ts
• jobs/check_hold_invoice_expired.ts
• ln/subscribe_invoice.ts
• util/index.ts

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Walkthrough

This PR consolidates the PerOrderIdMutex per-order locking utility from a Lightning Network-specific module into the shared utilities module, then updates all consumer code to import from the new location. The implementation moves unchanged; only its location and export sites are refactored.

Changes

PerOrderIdMutex Utility Consolidation

Layer / File(s)	Summary
Introduce PerOrderIdMutex in util module util/index.ts	Adds Mutex from async-mutex dependency, implements PerOrderIdMutex class that manages a map of per-orderId mutex instances with lock counting and lifecycle cleanup, and exports it.
Refactor ln/subscribe_invoice.ts to use util-exported PerOrderIdMutex ln/subscribe_invoice.ts	Updates util import to include PerOrderIdMutex and removes it from the module's public exports, transitioning from local implementation to shared utility.
Update consumer modules to import from util jobs/cancel_orders.ts, jobs/check_hold_invoice_expired.ts	Both job files update their imports to source PerOrderIdMutex from ../util instead of ../ln/subscribe_invoice.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• lnp2pBot/bot#746: Introduced initial use of PerOrderIdMutex in jobs/check_hold_invoice_expired.ts around per-order locking behavior.
• lnp2pBot/bot#705: Likely addresses related per-order mutex usage patterns in job scheduling.

Suggested reviewers

• grunch
• Catrya
• mostronatorcoder

Poem

🐰 Locks and keys find their home,
From subscribe's nest they roam,
To util's shared embrace,
Order mutexes find their place! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: refactoring PerOrderIdMutex and moving it from ln/subscribe_invoice.ts to util/index.ts for improved reusability, which is accurately reflected in all the file changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch refactor/move-per-order-id-mutex

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[ermeme]

Reviewed only the changes in scope of this PR. The refactor is clean and I did not find functional issues.

[grunch]

LGTM