feat: introduce WORKERS_POOL_ENABLED config to optionally disable worker thread pool

[quiet-node]

Description

This PR introduces the WORKERS_POOL_ENABLED configuration flag, allowing operators to optionally disable the worker thread pool (piscina). Key changes:

• Added WORKERS_POOL_ENABLED configuration variable in globalConfig.ts (defaults to true).
• Refactored WorkersPool.ts to support a "Local Bypass" mode using dynamic imports to load worker logic only when needed.
• Extracted WorkersErrorUtils.ts to provide standardized error serialization and reconstruction across thread boundaries, preventing circular dependencies.
• Updated blockWorker.ts and commonWorker.ts to leverage the new error utilities.
• Added tests

Related issue(s)

Fixes #4987

Testing Guide

1. Start up the Relay with WORKERS_POOL_ENABLED=false.
2. Verify that the Relay runs with a lower RSS baseline compared to when workers are enabled.
3. Run tests (e.g., eth_getLogs, eth_getBlockByNumber) and ensure they complete successfully on the main thread.
4. Verify that errors (e.g., MirrorNode errors) are still correctly propagated and mapped to JSON-RPC errors.

Checklist

• I've assigned an assignee to this PR and related issue(s) (if applicable)
• I've assigned a label to this PR and related issue(s) (if applicable)
• I've assigned a milestone to this PR and related issue(s) (if applicable)
• I've updated documentation (code comments, README, etc. if applicable)
• I've done sufficient testing (unit, integration, etc.)

[github-actions]

Test Results

0 tests  ±0   0 ✅ ±0   0s ⏱️ ±0s
0 suites ±0   0 💤 ±0 
0 files   ±0   0 ❌ ±0 

Results for commit d8931d9. ± Comparison against base commit 1cfee96.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

❌ Patch coverage is 95.09202% with 8 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...lay/src/lib/services/workersService/WorkersPool.ts	84.21%	6 Missing ⚠️
...ib/services/ethService/blockService/blockWorker.ts	66.66%	2 Missing ⚠️

@@            Coverage Diff             @@
##             main    #5070      +/-   ##
==========================================
- Coverage   95.90%   95.89%   -0.01%     
==========================================
  Files         144      145       +1     
  Lines       24740    24813      +73     
  Branches     1984     1993       +9     
==========================================
+ Hits        23727    23795      +68     
- Misses        985      990       +5     
  Partials       28       28              

Flag	Coverage Δ
config-service	98.49% <100.00%> (+<0.01%)	⬆️
relay	92.25% <88.60%> (-0.03%)	⬇️
server	88.39% <ø> (ø)
ws-server	97.90% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...ckages/config-service/src/services/globalConfig.ts	100.00% <100.00%> (ø)
...rvices/ethService/ethCommonService/commonWorker.ts	98.38% <100.00%> (ø)
...c/lib/services/workersService/WorkersErrorUtils.ts	100.00% <100.00%> (ø)
...s/relay/src/lib/services/workersService/workers.ts	98.57% <100.00%> (+0.13%)	⬆️
...ib/services/ethService/blockService/blockWorker.ts	95.10% <66.66%> (ø)
...lay/src/lib/services/workersService/WorkersPool.ts	97.84% <84.21%> (-2.16%)	⬇️

... and 1 file with indirect coverage changes

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[Ferparishuertas]

LGTM