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/tab_bar.py

@@ -0,0 +1,163 @@
+"""Custom kitty tab bar — Sethian status bar.
+
+Flat tab style (no powerline separators) + right-aligned status area.
+Shows user@ prefix for non-seth users.
+Status: git branch, CPU%, memory, uptime, hostname, clock.
+"""
+
+import os
+import subprocess
+from datetime import datetime
+
+from kitty.tab_bar import (
+    DrawData,
+    ExtraData,
+    Screen,
+    TabBarData,
+    as_rgb,
+)
+
+_user = os.environ.get("USER", "")
+_prefix = f"{_user}@" if _user and _user != "seth" else ""
+_hostname = os.uname().nodename
+
+# Nerd Font icons
+_ICON_BRANCH = "\ue725"
+_ICON_CPU = "\uf4bc"
+_ICON_MEM = "\uf035b"
+_ICON_UP = "\uf0aa"
+_ICON_HOST = "\uf108"
+_ICON_CLOCK = "\uf017"
+
+# Colors
+_ORANGE = as_rgb(0xD35400)
+_BLACK = as_rgb(0x000000)
+_DIM = as_rgb(0x666666)
+_TAB_BG = as_rgb(0x1A1A1A)
+_BAR_BG = as_rgb(0x0D0D0D)
+
+
+def _get_git_branch() -> str:
+    try:
+        r = subprocess.run(
+            ["git", "rev-parse", "--abbrev-ref", "HEAD"],
+            capture_output=True, text=True, timeout=1,
+        )
+        if r.returncode == 0:
+            return r.stdout.strip()
+    except Exception:
+        pass
+    return ""
+
+
+def _get_cpu_percent() -> str:
+    try:
+        with open("/proc/stat") as f:
+            parts = f.readline().split()
+        idle = int(parts[4]) + int(parts[5])
+        total = sum(int(p) for p in parts[1:])
+        prev_idle = getattr(_get_cpu_percent, "_i", 0)
+        prev_total = getattr(_get_cpu_percent, "_t", 0)
+        _get_cpu_percent._i = idle
+        _get_cpu_percent._t = total
+        if prev_total == 0:
+            return "..."
+        dt = total - prev_total
+        di = idle - prev_idle
+        return f"{(1.0 - di / dt) * 100:.0f}%" if dt else "0%"
+    except Exception:
+        return "?"
+
+
+def _get_memory() -> str:
+    try:
+        info = {}
+        with open("/proc/meminfo") as f:
+            for line in f:
+                p = line.split()
+                info[p[0].rstrip(":")] = int(p[1])
+        used = info["MemTotal"] - info.get("MemAvailable", info.get("MemFree", 0))
+        return f"{used / 1048576:.0f}/{info['MemTotal'] / 1048576:.0f}G"
+    except Exception:
+        return "?"
+
+
+def _get_uptime() -> str:
+    try:
+        with open("/proc/uptime") as f:
+            secs = int(float(f.read().split()[0]))
+        d, rem = divmod(secs, 86400)
+        h, rem = divmod(rem, 3600)
+        m = rem // 60
+        if d > 0:
+            return f"{d}d {h}h"
+        return f"{h}h {m}m" if h > 0 else f"{m}m"
+    except Exception:
+        return "?"
+
+
+def draw_tab(
+    draw_data: DrawData,
+    screen: Screen,
+    tab: TabBarData,
+    before: int,
+    max_tab_length: int,
+    index: int,
+    is_last: bool,
+    extra_data: ExtraData,
+) -> int:
+    # Build tab title
+    title = tab.title
+    if _prefix:
+        title = f"{_prefix}{title}"
+    label = f" {index - 1}: {title} "
+
+    # Truncate if needed
+    if len(label) > max_tab_length:
+        label = label[: max_tab_length - 1] + "\u2026"
+
+    # Draw the tab
+    if tab.is_active:
+        screen.cursor.fg = _BLACK
+        screen.cursor.bg = _ORANGE
+        screen.cursor.bold = True
+    else:
+        screen.cursor.fg = _DIM
+        screen.cursor.bg = _TAB_BG
+        screen.cursor.bold = False
+
+    screen.draw(label)
+    screen.cursor.bold = False
+
+    # Small gap between tabs
+    screen.cursor.fg = _DIM
+    screen.cursor.bg = _BAR_BG
+    screen.draw(" ")
+
+    end = screen.cursor.x
+
+    # Right-aligned status on last tab
+    if is_last:
+        sep = "  "
+        cells: list[tuple[str, int]] = []
+
+        branch = _get_git_branch()
+        if branch:
+            cells += [(_ICON_BRANCH + " ", _ORANGE), (branch, _DIM), (sep, _DIM)]
+
+        cells += [(_ICON_CPU + " ", _ORANGE), (_get_cpu_percent(), _DIM), (sep, _DIM)]
+        cells += [(_ICON_MEM + " ", _ORANGE), (_get_memory(), _DIM), (sep, _DIM)]
+        cells += [(_ICON_UP + " ", _ORANGE), (_get_uptime(), _DIM), (sep, _DIM)]
+        cells += [(_ICON_HOST + " ", _ORANGE), (_hostname, _DIM), (sep, _DIM)]
+        cells += [(_ICON_CLOCK + " ", _ORANGE), (datetime.now().strftime("%H:%M"), _DIM), (" ", _DIM)]
+
+        total_len = sum(len(t) for t, _ in cells)
+        right_pos = screen.columns - total_len
+        if right_pos > end:
+            screen.cursor.x = right_pos
+            for text, fg in cells:
+                screen.cursor.fg = fg
+                screen.cursor.bg = _BAR_BG
+                screen.draw(text)
+
+    return end