[eas-cli][eas-json] use node18 as tsconfig base

[quinlanj]

Why

Followup from #2736 (comment)

Standardize TypeScript configuration across packages by adopting the recommended Node.js 18 TypeScript configuration. This helps ensure consistent TypeScript settings and reduces configuration duplication.

How

• Added @tsconfig/node18 dependency to eas-cli and eas-json packages
• Extended the base Node 18 TypeScript configuration in both packages
• Removed redundant compiler options that are already included in the Node 18 preset
• Updated module resolution strategy to explicitly use "node"

Test Plan

Current tests pass

[quinlanj]

• [eas-cli][eas-json] use node18 as tsconfig base #2739 👈 (View in Graphite)
• main

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[github-actions]

Size Change: -22.7 kB (-0.04%)

Total Size: 53.4 MB

Filename	Size	Change
./packages/eas-cli/dist/eas-linux-x64.tar.gz	53.4 MB	-22.7 kB (-0.04%)

_{compressed-size-action}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 52.51%. Comparing base (5e5b55f) to head (9e79e23).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2739   +/-   ##
=======================================
  Coverage   52.51%   52.51%           
=======================================
  Files         583      583           
  Lines       22582    22582           
  Branches     4452     4452           
=======================================
  Hits        11856    11856           
  Misses      10691    10691           
  Partials       35       35           

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[github-actions]

Subscribed to pull request

File Patterns	Mentions
**/*	@szdziedzic, @khamilowicz, @sjchmiela, @radoslawkrzemien

Generated by CodeMention

[szdziedzic]

looks reasonable (after merge conflicts are resolved and tests stop failing)

[github-actions]

✅ Thank you for adding the changelog entry!