Fix version-directory cleanup race and run cloudformation-validate in a worker thread

[satyakigh]

Description of changes:

Database (FileDB and LMDB)

Each store keeps its data in a versioned directory (filedb/v4, lmdb/v7) and deletes older versions two minutes after startup. When 1.12.0 moved FileDB from v3 to v4, it deleted filedb/v3 while older language server processes on the same machine (other IDE windows, other IDEs) were still using it, so those processes failed on every read. That is the files.scan.error spike. Each store now writes a .heartbeat file in its own directory at startup and every 60 seconds, and cleanup skips any older directory that was used in the last 24 hours. Skipped directories are counted as oldVersion.cleanup.skipped.

cfn-validate

Every validate.error in production is the cloudformation-validate engine running out of memory on templates with many conditional (Fn::If) properties. The engine ran on the main thread, so a large template froze the language server for seconds, and once it ran out of memory every later validation failed too. The engine now runs in a worker thread with the same 128 MB heap limit as cfn-lint, and each validation has a 30 second timeout. If the worker crashes, exits, or times out, it is terminated, its memory is released, and validation is turned off for the rest of the session with a single validate.error. The main thread is never blocked, and one template is validated at a time.

Worker and retry failures now use typed error classes (WorkerExitError, WorkerFailureError, RetryError) instead of plain Error; messages are unchanged.

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[github-code-quality]

Code Coverage Overview

Languages: TypeScript

TypeScript / code-coverage/vitest

The overall line coverage in commit 1a9dde0 in the errors-db branch remains at 91%, unchanged from commit e1dc3fe in the main branch.

Show a line coverage summary of the most impacted files.

File	main e1dc3fe	errors-db 1a9dde0	+/-
src/telemetry/S...pedTelemetry.ts	96%	87%	-9%
src/datastore/F...StoreFactory.ts	93%	93%	0%
src/datastore/L...StoreFactory.ts	90%	90%	0%
src/datastore/V...ionDirectory.ts	100%	100%	0%
src/services/cf...orkerManager.ts	87%	87%	0%
src/utils/error...ErrorClasses.ts	100%	100%	0%
src/services/cf...idateService.ts	98%	100%	+2%
src/datastore/DataStore.ts	92%	94%	+2%
src/services/cf...lidateEngine.ts	93%	97%	+4%
src/datastore/l...b/LMDBModule.ts	0%	100%	+100%

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_{Updated October 09, 2026 22:13 UTC}

[mrinaudo-aws]

LGTM

The merge-base changed after approval.