feat(themes): add theme system with starship integration

- Add theme selection system with 5 predefined themes
- Implement Catppuccin Mocha, Dracula, Gruvbox Dark, Nord, and Tokyo Night
- Each theme includes NvChad integration and starship prompt configuration
- Support for custom color palettes and consistent formatting
- Interactive theme selection with numbered menu

lib/themes/gruvbox.sh

@@ -0,0 +1,92 @@
+#!/bin/bash
+THEME_DISPLAY_NAME="Gruvbox Dark"
+NVCHAD_THEME="gruvbox"
+
+write_starship_config() {
+  cat >"$1" <<'TOML'
+palette = "gruvbox_dark"
+format = """$directory$git_branch$git_status$character"""
+
+[directory]
+style = "bold fg:bright-yellow"
+truncation_length = 3
+
+[git_branch]
+style = "bold fg:bright-green"
+format = " [$branch]($style) "
+
+[git_status]
+style = "bold fg:bright-red"
+
+[character]
+success_symbol = "[❯](bold fg:bright-green)"
+error_symbol = "[❯](bold fg:bright-red)"
+
+[palettes.gruvbox_dark]
+bright-yellow = "#fabd2f"
+bright-green = "#b8bb26"
+bright-red = "#fb4934"
+bright-blue = "#83a598"
+bright-purple = "#d3869b"
+bright-aqua = "#8ec07c"
+bright-orange = "#fe8019"
+TOML
+}
+
+write_zellij_config() {
+  cat >"$1" <<'KDL'
+theme "gruvbox-dark"
+default_layout "default"
+default_mode "normal"
+pane_frames false
+simplified_ui true
+mouse_mode false
+
+keybinds {
+    shared {
+        bind "Alt h" { MoveFocusOrTab "Left"; }
+        bind "Alt l" { MoveFocusOrTab "Right"; }
+        bind "Alt j" { MoveFocus "Down"; }
+        bind "Alt k" { MoveFocus "Up"; }
+        bind "Alt n" { NewPane "Down"; }
+        bind "Alt v" { NewPane "Right"; }
+        bind "Alt f" { ToggleFloatingPanes; }
+        bind "Alt t" { NewTab; }
+    }
+}
+
+themes {
+    gruvbox-dark {
+        fg "#ebdbb2"
+        bg "#282828"
+        black "#1d2021"
+        red "#cc241d"
+        green "#98971a"
+        yellow "#d79921"
+        blue "#458588"
+        magenta "#b16286"
+        cyan "#689d6a"
+        white "#a89984"
+        orange "#d65d0e"
+    }
+}
+KDL
+}
+
+write_lazygit_config() {
+  cat >"$1" <<'YAML'
+gui:
+  theme:
+    activeBorderColor:
+      - "#fabd2f"
+      - bold
+    inactiveBorderColor:
+      - "#665c54"
+    selectedLineBgColor:
+      - "#3c3836"
+    cherryPickedCommitFgColor:
+      - "#b8bb26"
+    defaultFgColor:
+      - "#ebdbb2"
+YAML
+}