Align SoftwareX metadata with v1.0.0

[gparadis]

Summary

• replace in-repo SoftwareX beta/submission-branch placeholders with final v1.0.0 release/tag/PyPI install metadata
• update manuscript release prose and software environment context to FHOPS 1.0.0 / Python 3.11--3.12
• make the in-repo manuscript PDF target generate and use the bundled Elsevier class source instead of requiring a global elsarticle.cls
• document synchronization expectation between in-repo SoftwareX assets and standalone fhops-manuscript packaging
• update roadmap/release prep/changelog traceability for v1.0.0 GA: align SoftwareX metadata with final release #17

Closes #17.

Verification

• rg -n "v1\.0\.0-beta1|softwarex-manuscript|will be tagged|minted alongside" docs/softwarex/manuscript returned no matches
• rg -n "1\.0\.0a2|1\.0\.0-alpha2|release candidate|beta" docs/softwarex/manuscript docs/softwarex/README.md returned no matches
• .venv/bin/ruff format src tests
• .venv/bin/ruff check src tests
• .venv/bin/mypy src
• .venv/bin/pytest (299 passed, 210 skipped, 61 warnings)
• .venv/bin/pre-commit run --all-files
• PANDOC_DIR=$(...) PATH="$PANDOC_DIR:$PATH" .venv/bin/sphinx-build -b html docs _build/html -W
• make clean && make pdf from docs/softwarex/manuscript/ (passes; existing overfull/underfull LaTeX box warnings remain)