High-risk tag killer-zone rule for issue #61

[segior340-source]

Summary

Implements a practical first step for the suggestions in #61 about raising the cost of multi-account illegal-content distribution.

What this PR does

• Adds a new visibility-filtering rule that treats specific high-risk tags as “killer-zone” signals.
• Posts containing these tags are dropped from recommendations (author can still see their own posts).
• Documents the real objective clearly:
  • Not just removing tags (actors can rotate them quickly)
  • Triggering alerts and future reputation/visibility penalties for posters and engagers
  • Preparing for negative-reputation propagation when content under these tags is later banned

Tags currently covered

• teenageer
• nolimits
• momsonn
• omegle

Limitations

Full automatic engager penalty, watchlist, and short media hold for low-trust accounts are not fully implementable with the currently open-sourced surfaces. The code and comments document the intended direction for future work.

Closes nothing yet — this is offered for discussion and possible iteration related to #61.