fix(ci): make release publishing retry-safe

[hadrien]

Problem

• Release errors were treated as no-release outcomes after version refs could be created.
• The public docs extra exposed a Git dependency that PyPI rejects.
• GitHub Pages rejects tag deployments, and docs shared the release concurrency group.

Solution

• Build, validate, and upload to PyPI inside Semantic Release before it commits or tags; stage the synchronized lockfile and make retries safe.
• Keep docs-only dependencies in a development group and deploy Pages from main with independent concurrency.
• Use the authenticated release identity and classify supported non-chore commits as releases.

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 (55e328d).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #139   +/-   ##
=======================================
  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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