fix: delete encoded video urls

[Priveetee]

Summary

• Normalize encoded video URL tail parameters before route handlers delete persisted rows.
• Reuse the same parsing for favorites, playlists, watch-later, progress, and blocked videos.
• Add regression tests for POST then DELETE with encoded YouTube watch URLs.

Tests

• JAVA_HOME=/usr/lib/jvm/java-21-openjdk ./gradlew test