feat: custom kitty tab bar with system status + install scripts

Custom tab_bar.py with flat tabs, right-aligned status area (git branch,
CPU%, memory, uptime, hostname, clock) using Nerd Font icons. F12/Shift+F12
toggle for tab bar. Added Kitty-setup.md, theme-setup.md, and install
scripts for kitty-only and full Debian theme deployment.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

kitty/toggle-tab-bar.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+# Toggle kitty tab bar via kitty @ using KITTY_LISTEN_ON
+STATE_FILE="/tmp/kitty-tab-bar-state"
+SOCK="${KITTY_LISTEN_ON}"
+
+if [ -z "$SOCK" ]; then
+    # Fallback: find socket by parent kitty PID
+    SOCK="unix:/tmp/kitty-${KITTY_PID}"
+fi
+
+if [ -f "$STATE_FILE" ] && [ "$(cat "$STATE_FILE")" = "hidden" ]; then
+    kitty @ --to "$SOCK" load-config /home/seth/.config/kitty/tab-bar-show.conf
+    echo "visible" > "$STATE_FILE"
+else
+    kitty @ --to "$SOCK" load-config /home/seth/.config/kitty/tab-bar-hide.conf
+    echo "hidden" > "$STATE_FILE"
+fi