feat: Adds transaction pool funcitonality

[konstantinabl]

Description

This PR introduces the new transaction pool feature sitting behind the ENABLE_TX_POOL flag.

The details can be found in the doc create for it https://github.com/hiero-ledger/hiero-json-rpc-relay/pull/4454/files#diff-30f3b82da50d90485c8cddfec36b0a03b7d442dbe7062c07f0c517a8143a387f

Related issue(s)

Fixes #3960

Testing Guide

Additional work needed (optional)

N/A

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

 20 files  ± 0  269 suites  +3   21m 58s ⏱️ +44s
778 tests + 9  774 ✅ +12  4 💤 ±0  0 ❌  - 3 
794 runs  +10  790 ✅ +13  4 💤 ±0  0 ❌  - 3 

Results for commit f908c27. ± Comparison against base commit b7c40e7.

This pull request removes 2 and adds 11 tests. Note that renamed tests count towards both.

"after all" hook for "@release should return the code through a websocket" ‑ RPC Server Acceptance Tests Acceptance tests @web-socket-batch-2 eth_getCode "after all" hook for "@release should return the code through a websocket"
test getAsync operation ‑ RPC Server Acceptance Tests Acceptance tests @cache-service Acceptance Tests for shared cache fallback to local cache in case of Redis error test getAsync operation

should fail with WRONG_NONCE when a transaction with very high nonce has been sent ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature should fail with WRONG_NONCE when a transaction with very high nonce has been sent
should fail with WRONG_NONCE when multiple transactions have been sent simultaneously ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = false should fail with WRONG_NONCE when multiple transactions have been sent simultaneously
should have difference between pending and latest nonce when a single transaction has been sent ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = true should have difference between pending and latest nonce when a single transaction has been sent
should have difference between pending and latest nonce when multiple transactions have been sent simultaneously ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = true should have difference between pending and latest nonce when multiple transactions have been sent simultaneously
should have equal nonces (pending and latest) after CN reverted transaction ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = true should have equal nonces (pending and latest) after CN reverted transaction
should have equal nonces (pending and latest) after multiple CN reverted transactions ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = true should have equal nonces (pending and latest) after multiple CN reverted transactions
should have equal nonces (pending and latest) after successfully validated transaction ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = true should have equal nonces (pending and latest) after successfully validated transaction
should have equal nonces (pending and latest) for contract reverted transaction ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = true should have equal nonces (pending and latest) for contract reverted transaction
should return equal nonces (pending and latest) when transaction has been sent ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = false should return equal nonces (pending and latest) when transaction has been sent
should return latest nonce after transaction has been sent  ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-1 RPC Server Acceptance Tests RPC Server Acceptance Tests Transaction related RPC Calls Transaction Pool feature ENABLE_TX_POOL = false should return latest nonce after transaction has been sent 
…

♻️ This comment has been updated with latest results.

[quiet-node]

Hey team great work overall! Since this is a big PR it naturally raises quite many questions on my side. I didn’t get a chance to bring them up during the individual PRs, so I’m leaving all my concerns and feedback here. Well tbh having the full picture actually makes it easier to spot things.

Anywho my feedback can be controversial so I’d love to hear your thoughts on them

[quiet-node]

LGTM! Great work!

[codecov]

Codecov Report

❌ Patch coverage is 89.32584% with 76 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
packages/relay/src/lib/types/transactionPool.ts	0.00%	70 Missing ⚠️
packages/relay/src/lib/clients/cache/redisCache.ts	92.68%	3 Missing ⚠️
...ckages/relay/src/lib/clients/redisClientManager.ts	96.61%	2 Missing ⚠️
...s/relay/src/lib/clients/cache/IRedisCacheClient.ts	0.00%	1 Missing ⚠️

@@            Coverage Diff             @@
##             main    #4454      +/-   ##
==========================================
- Coverage   96.23%   95.52%   -0.72%     
==========================================
  Files         121      127       +6     
  Lines       20001    20447     +446     
  Branches     1755     1760       +5     
==========================================
+ Hits        19247    19531     +284     
- Misses        735      897     +162     
  Partials       19       19              

Flag	Coverage Δ
config-service	98.81% <100.00%> (+0.01%)	⬆️
relay	90.92% <86.91%> (-0.25%)	⬇️
server	88.85% <ø> (ø)
ws-server	98.04% <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)
packages/relay/src/lib/clients/sdkClient.ts	95.82% <100.00%> (+0.03%)	⬆️
packages/relay/src/lib/debug.ts	99.37% <100.00%> (-0.01%)	⬇️
packages/relay/src/lib/eth.ts	99.57% <100.00%> (+<0.01%)	⬆️
packages/relay/src/lib/precheck.ts	98.68% <100.00%> (+<0.01%)	⬆️
packages/relay/src/lib/relay.ts	98.61% <100.00%> (+0.78%)	⬆️
...elay/src/lib/services/cacheService/cacheService.ts	97.49% <100.00%> (+0.47%)	⬆️
...rvices/ethService/accountService/AccountService.ts	96.53% <100.00%> (-0.02%)	⬇️
...thService/transactionService/TransactionService.ts	98.86% <100.00%> (+1.62%)	⬆️
packages/relay/src/lib/services/index.ts	100.00% <100.00%> (ø)
... and 8 more

... and 1 file with indirect coverage changes

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