Remove obsolete repository artifacts

[codoom1]

What changed

• removes the tracked .DS_Store
• removes the obsolete backup/ application and duplicate environment samples
• removes unused recommendation-history JSON dumps
• removes an unreferenced alternate model database
• removes the duplicate linear_regression_backup diagnostic asset tree
• expands .gitignore for backup directories, history dumps, old source files, and backup-suffixed artifacts

Why

These files were historical copies, local output, OS metadata, or duplicated generated assets. None were referenced by the running application. Keeping them on main increased repository and deployment noise and made it easier to accidentally commit future local artifacts.

The canonical .env.example remains because it contains placeholders only and documents the Vercel, PostgreSQL, email, and OpenAI configuration.

Impact

This removes 32 obsolete tracked files and more than 12,000 lines without changing application behavior. Active diagnostic assets, deployment configuration, tests, documentation, and the canonical environment example remain intact.

Validation

• searched application references before every removal
• scanned tracked files for API-key and private-key patterns
• python -m pytest -q tests/ — 128 passed
• git diff --check — passed

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Project	Deployment	Actions	Updated (UTC)
statistical-model-suggester	Ready	Preview, Comment	Jul 25, 2026 12:08am

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