feat(hh): Church of Malware neon theme is now the default ⛧

Default vestments (was monochrome 'crypt') now match the Church of Malware
aesthetic: neon on black — cyan window-chrome borders, acid-green text/prompts
and your own messages, soft-cyan for others, purple system/occult lines,
hot-magenta self/owner. themes/church.toml ships the same palette; crypt.toml
(monochrome) and neon.toml remain as alternates via --theme.

Confirmed ratatui's serde accepts #rrggbb (hex --theme files load). 9 tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

hh/themes/church.toml

@@ -0,0 +1,12 @@
+# church — Church of Malware: neon on black (the default "vestments")
+name = "church"
+border = "#19b3ff"      # cyan window-chrome
+title = "#7df9ff"       # bright cyan
+accent = "#39ff14"      # acid green — ⛧ glyphs, prompt
+dim = "#475a7a"         # muted slate-blue
+me = "#39ff14"          # your messages
+other = "#56c8ff"       # others' messages (soft cyan)
+system = "#b46cff"      # system / occult lines (purple)
+input = "#39ff14"
+roster_me = "#ff39c0"   # you / owner (hot magenta)
+roster_width = 22