Split workspace report computation

[codeforester]

Fixes #1463

Summary

• split workspace status computation into base_projects.workspace_statuses
• split workspace check computation into base_projects.workspace_checks
• keep base_projects.workspace_reports as the compatibility facade for render helpers and existing imports

Validation

• /private/tmp/base-python-train-venv/bin/python -m pytest cli/python/base_projects/tests -q
• /private/tmp/base-python-train-venv/bin/pylint cli/python/base_projects/workspace_reports.py cli/python/base_projects/workspace_statuses.py cli/python/base_projects/workspace_checks.py cli/python/base_projects/workspace_report_common.py cli/python/base_projects/tests/test_workspace_reports_structure.py
• /private/tmp/base-python-train-venv/bin/python -m compileall cli/python/base_projects
• git diff --check
• env BASE_BASH_LIBS_DIR=/Users/rameshhp/work/base-bash-libs/lib/bash BASE_CACHE_DIR=/private/tmp/base-1463-workspace-smoke bin/basectl workspace status --workspace /Users/rameshhp/work --format json