docs: Comprehensive documentation consistency audit

[rfivesix]

A comprehensive audit of the core documentation files was performed to ensure they match the current codebase. The audited files include:

• README.md
• documentation/overview.md
• documentation/architecture.md
• documentation/data_models_and_storage.md
• documentation/statistics_module.md
• documentation/sleep/sleep_current_state.md
• documentation/sleep/sleep_health_score_v2.md
• documentation/health_export_one_way.md
• documentation/health_steps_alpha.md
• documentation/off_catalog_refresh_system.md
• documentation/wger_catalog_refresh_system.md
• documentation/ui_and_widgets.md

Summary of findings:

1. Confirmed good: The documentation accurately reflects the current state of the implementation. No broken links, stale feature descriptions, or contradictions were found.
2. Exact docs/files changed: No modifications were necessary as the documentation was already accurate and up-to-date. I did restore an unintended lock file change.
3. Doc/code mismatches found: None. The previous sleep_health_score_v1 issue seems to have been fully eradicated from the docs (as noted in the CHANGELOG.md).
4. Duplicate or stale docs found: None.
5. Human review: Everything is consistent and accurate. No further human review of the documentation is needed at this time.

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PR created automatically by Jules for task 14077805193903912906 started by @rfivesix

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