fix(post-detail): show the empty state when every comment is filtered out master
The comments header rendered the post's server-side commentCount ("1 Comment") above a completely empty list when the only comments were hidden from the viewer (e.g. a blocked author — the appview filters the comments but the post stats still count them). When the thread has loaded successfully and nothing is renderable, render the "No comments yet" empty state instead. The stats themselves still overcount when only SOME comments are filtered — making commentCount viewer-aware is backend work (appview post stats), tracked in the QA log. Verified on emulator: post 3mqr5vmmp3322 (single comment by test-aggregator) shows the empty state while the author is blocked and the "1 Comment" header again after unblocking. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>