🛡️ Sentinel: [CRITICAL] Fix SQL injection risk via assertion bypass

[davidjuarezdev]

🚨 Severity: CRITICAL
💡 Vulnerability: The streamrip/db.py module relied on Python's assert statement to validate keyword argument keys against expected columns before unpacking them into dynamically constructed SQL queries in the contains() method, and lacked validation entirely in the remove() method. Since assert statements are stripped when Python is run with optimizations (-O), an attacker could supply malicious keyword argument keys (which bypass Python's strict identifier restrictions) leading to SQL injection.
🎯 Impact: Potential for arbitrary code execution or data exposure via SQL injection if the application is run in optimized mode and processing untrusted input.
🔧 Fix: Replaced the assert statement with an explicit if statement raising ValueError in contains(), and added the same explicit key validation to remove().
✅ Verification: Ran ruff check and pytest to ensure no regressions. Added a Sentinel journal entry documenting the learning.

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PR created automatically by Jules for task 11038255197215758585 started by @davidjuarezdev