Hide faction thread delete controls

[Cyber-preacher]

Summary

• Removes the UI delete buttons for faction threads and faction thread replies.
• Leaves faction status controls and reply posting intact.
• Keeps the API surface unchanged so existing backend behavior is not disturbed.

Why

This ships the one remaining Phase 84 local change and avoids exposing delete controls on faction discussion surfaces.

Validation

• yarn prettier:check
• yarn typecheck
• yarn build
• git diff --check