feat: Nerd Font support, clipboard paste, and PTY environment fixes

- Add ttyd-nerd-font submodule with embedded JetBrains Mono Nerd Font
  for proper icon rendering in browser via ttyd
- Add Ctrl+Shift+V / Shift+Insert paste support in ttyd frontend
- Strip Zellij env vars from PTY child processes to prevent workspace
  terminal from inheriting Zellij session context
- Launch PTY commands through login shell for proper PATH resolution
- Use /etc/passwd shell lookup instead of $SHELL (Zellij overrides it)
- Soften ANSI 256-color palette to match modern dark themes
- Handle Nerd Font PUA glyphs as width 1 in pyte terminal emulator
- Fix brightmagenta typo in pyte graphics
- Update install script to build ttyd from submodule source
- Add web deployment TODO items for image paste and context menu

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

deploy/clide-web.service

@@ -13,7 +13,8 @@ WorkingDirectory=/mnt/media/Projects
 # -W            : Writable (allows input)
 # -a            : Allow URL arguments (passes ?project=X as command arg)
 # -t fontSize=14: Terminal font size
-ExecStart=/usr/local/bin/ttyd -p 8888 -W -a -t fontSize=14 /usr/local/bin/clide-launcher
+# -t fontFamily: Use embedded JetBrains Mono Nerd Font (from ttyd-nerd-font fork)
+ExecStart=/usr/local/bin/ttyd -p 8888 -W -a -t fontSize=14 -t 'fontFamily=JetBrains,monospace' /usr/local/bin/clide-launcher
 
 # Kill all child processes (ttyd → zellij → clide → claude)
 KillMode=control-group