[oob] add nx to octi/opencti repo (#13767)

[delemaf]

Proposed changes

• Add nx as a task orchestrator for the opencti monorepo
• Define nx projects and targets for existing workspaces (front, graphql, worker, client-python)
• Expose unified root commands :

yarn deps   # install dependencies across projects
yarn build  # build all projects
yarn lint   # lint all projects
yarn test   # run all tests and front e2e 
yarn dev    # start backend, frontend and a worker

Related issues

• OOB 🥷 Add nx to handle yarn in opencti sub repo #13767

Checklist

• I consider the submitted work as finished
• I tested the code for its functionality
• I wrote test cases for the relevant uses case (coverage and e2e)
• I added/update the relevant documentation (either on github or on notion)
• Where necessary I refactored code to improve the overall quality

Further comments

Nx is introduced in a non-invasive way: it only orchestrates existing commands and does not change build logic, runtime behavior, or enable caching. This improves task coordination and maintainability without impacting current workflows.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 30.82%. Comparing base (23e924e) to head (6985379).

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #13779      +/-   ##
==========================================
- Coverage   30.82%   30.82%   -0.01%     
==========================================
  Files        2910     2910              
  Lines      192184   192184              
  Branches    39167    39166       -1     
==========================================
- Hits        59241    59238       -3     
- Misses     132943   132946       +3     

Flag	Coverage Δ
opencti	30.82% <ø> (-0.01%)	⬇️
opencti-front	2.46% <ø> (ø)
opencti-graphql	68.20% <ø> (-0.01%)	⬇️

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