Integrate Firebase Auth

[bonk1t]

• Authenticate users with Firebase Auth using tokens sent in the Bearer header.
• Update tests
• Update README.md files
• Refactor, remove get_current_active_user
  Unrelated changes:
• Ensure HTTPStatus usage consistency
• Update packages, poetry.lock, requirements.txt.

[codecov]

Codecov Report

Attention: Patch coverage is 81.66667% with 11 lines in your changes are missing coverage. Please review.

Project coverage is 89.45%. Comparing base (6420e51) to head (331a9d0).
Report is 1 commits behind head on main.

Files	Patch %	Lines
nalgonda/routers/v1/api/agent.py	50.00%	4 Missing ⚠️
nalgonda/routers/v1/api/tool.py	72.72%	3 Missing ⚠️
nalgonda/routers/v1/api/session.py	66.66%	2 Missing ⚠️
nalgonda/routers/v1/api/agency.py	90.00%	1 Missing ⚠️
nalgonda/routers/v1/api/message.py	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #28      +/-   ##
==========================================
+ Coverage   87.91%   89.45%   +1.54%     
==========================================
  Files          54       52       -2     
  Lines        1390     1309      -81     
==========================================
- Hits         1222     1171      -51     
+ Misses        168      138      -30     

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