ci: pass bumped version and post-bump ref to docs jobs in release flow (#806)

## Summary

The v3.0.0 release versioned the docs as `2.5` instead of `3.0`
(overwriting v2.5 content with v3). Root cause:
`manual_version_docs.yaml` reads `uv version --short` from a checkout of
the workflow's dispatch ref (pre-bump), so the job sees the old version.
Run
[#26156928273](https://github.com/apify/apify-client-python/actions/runs/26156928273)
logged `Version: 2.5.1, Major.Minor: 2.5, Major: 2`; bad output is
commit e0a0bc8.

## Fix

- `manual_version_docs.yaml` — optional `version_number` input; snapshot
step uses it when set, falls back to `uv version --short` for manual
dispatch.

Companion data-restore PR: #808.