fix: resolve lint errors across repo and strengthen CI enforcement

[bootcodes]

Description

This PR strengthens the CI pipeline by adding automated lint checks and resolves all lint errors across the codebase.

1. Lint Error Resolution:

• Fixed all lint errors

2. Eslint config:

• Scoped the eslint to src/ and test/ folder

3. CI Pipeline Enhancement

• Created new .github/workflows/lint.yml workflow that runs on every PR
• Lint checks now block PR merges if any errors are found
• Adds a separate lint-type-aware CI job that runs no-floating-promises and no-misused-promises on PRs only via eslint.config.ci.mjs. Keeps local linting fast by deferring expensive type-aware rules to CI.

4. Husky hook

• Added pre-push hook to run npm build

Related issue(s)

Fixes #4700

Testing Guide

1. Verify Lint Status: npm run lint
2. Verify Type Checking: npx tsc --noEmit
3. Verify Build: npm run build

Changes from original design (optional)

Scoped eslint config to src and test folder - see eslint.config.mjs

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.)

[codacy-production]

Not up to standards ⛔

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Metrics 0 complexity · 0 duplication

Metric	Results
Complexity	0
Duplication	0

View in Codacy

_{TIP This summary will be updated as you push new changes. Give us feedback}

[codecov]

Codecov Report

❌ Patch coverage is 30.49645% with 98 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
eslint.config.ci.mjs	0.00%	29 Missing ⚠️
eslint.config.mjs	0.00%	18 Missing ⚠️
src/relay/lib/clients/mirrorNodeClient.ts	52.00%	12 Missing ⚠️
...thService/transactionService/TransactionService.ts	0.00%	7 Missing ⚠️
src/index.ts	0.00%	6 Missing ⚠️
src/relay/lib/model.ts	0.00%	4 Missing ⚠️
...elay/lib/services/lockService/LocalLockStrategy.ts	0.00%	3 Missing ⚠️
src/config-service/commands/printEnvs.ts	0.00%	2 Missing ⚠️
src/config-service/services/index.ts	33.33%	0 Missing and 2 partials ⚠️
src/relay/lib/precheck.ts	0.00%	2 Missing ⚠️
... and 10 more

❌ Your patch check has failed because the patch coverage (30.49%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.
❌ Your project check has failed because the head coverage (73.50%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.

❗ There is a different number of reports uploaded between BASE (c95f3f9) and HEAD (4a9acd4). Click for more details.

HEAD has 18 uploads less than BASE

Flag	BASE (c95f3f9)	HEAD (4a9acd4)
	22	4

@@             Coverage Diff             @@
##             main    #5228       +/-   ##
===========================================
- Coverage   95.93%   73.50%   -22.43%     
===========================================
  Files         146      147        +1     
  Lines       25140    25181       +41     
  Branches     2044      848     -1196     
===========================================
- Hits        24117    18510     -5607     
- Misses       1001     6646     +5645     
- Partials       22       25        +3     

Files with missing lines	Coverage Δ
src/relay/lib/clients/cache/localLRUCache.ts	72.23% <100.00%> (-27.17%)	⬇️
src/relay/lib/clients/sdkClient.ts	55.22% <100.00%> (-40.89%)	⬇️
src/relay/lib/constants.ts	100.00% <100.00%> (ø)
src/relay/lib/db/types/hbarLimiter/errors.ts	79.31% <100.00%> (-20.69%)	⬇️
src/relay/lib/decorators/rpcMethod.decorator.ts	100.00% <100.00%> (ø)
src/relay/lib/factories/blockFactory.ts	47.03% <100.00%> (-51.78%)	⬇️
src/relay/lib/factories/cacheClientFactory.ts	100.00% <100.00%> (ø)
...ervices/ethService/accountService/accountWorker.ts	65.09% <100.00%> (-32.08%)	⬇️
...b/services/ethService/blockService/BlockService.ts	74.60% <100.00%> (-23.83%)	⬇️
...ib/services/ethService/blockService/blockWorker.ts	64.96% <100.00%> (-30.57%)	⬇️
... and 23 more

... and 61 files with indirect coverage changes

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[jasuwienas]

Overall, it looks great. I’m just not sure whether it’s correct to treat null the same as undefined in places where we previously distinguished between the two. I don’t think this PR should introduce business-level changes to the application, even if they make sense.

[quiet-node]

Great work overall! Left some items

[quiet-node]

I supposed these are changed because the linting is complaining?

[bootcodes]

yes they are : It's not a problem here though
> null != undefined false
It won't pass the condition if null or undefined values are encountered

[quiet-node]

Would it make sense to run npm run lint here instead of the full npm run build? A full build on every push might slow down the local development workflow significantly. The build check could be deferred to CI where it already runs.

[quiet-node]

Well actually doesn't the pre-commit hook already handles linting via lint-staged for each commit? If it doesn't work should we just fix it instead of adding a new hook?

[bootcodes]

npm run lint on pre-push would be redundant with lint-staged on pre-commit hook. But npm run build isn't the right gate either. I'm more inclined to have tsc --noEmit on pre-push hook, as currently it doesn't invoke tsc so type errors slip through and only appear in CI. We could catch those errors early without significant bottleneck on local development