fix(ci): make release publishing retry-safe

[hadrien]

Problem

• Release references could exist before PyPI accepted the package.
• Published documentation dependencies exposed a Git URL rejected by PyPI.
• GitHub Pages rejected tag-based documentation deployments.
• Semantic Release removed Twine credentials from its build subprocess.

Solution

• Publish retry-safe packages before creating release references.
• Forward Twine credentials explicitly into the release build.
• Authenticate release pushes with the configured personal token.
• Keep documentation dependencies outside published extras.
• Deploy documentation from main under independent concurrency.
• Treat Codecov uploads as non-blocking reports.

Bead: fs-oc8

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.74%. Comparing base (2419e9e) to head (9f3d8c5).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #142   +/-   ##
=======================================
  Coverage   97.74%   97.74%           
=======================================
  Files           1        1           
  Lines         133      133           
  Branches        7        7           
=======================================
  Hits          130      130           
  Misses          3        3           

Flag	Coverage Δ
fastapi-post121	97.74% <ø> (ø)
fastapi-pre121	97.74% <ø> (ø)
sqlmodel	97.74% <ø> (ø)

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