[Sync] adopt unified stow layout from the private repo

Mirrors the private dots tree at 900bdda: one shared base plus per-host
overlays, replacing the old flat .config/ layout (last synced 2026-06-28).

- packages: common/ gui/ wm/ lw/ fl/ + install.sh and bin/ tooling (dotsync,
  reconcile-hyde.sh)
- new README (layout, deploy order, HyDE dependency), plus ToDo.md and
  HYDE-UPDATE.md
- current HyDE waybar rig (layouts/, cava), pi agent extensions, claude/
  config, tmux, presenterm, aichat roles
- drops stale duplicates and generated cruft that should never have been
  tracked: the second top-level .pi/ copy, btop.log, zellij config.kdl.bak,
  fish_variables, nvim codecompanion.lua
- .pi/agent/auth.json is gitignored now; auth.json.example ships instead
- fl/ and wm/ hypr themes/ stay untracked (HyDE-generated per machine, per
  the root .gitignore)

common/.config/bat/config

@@ -0,0 +1,34 @@
+# This is `bat`s configuration file. Each line either contains a comment or
+# a command-line option that you want to pass to `bat` by default. You can
+# run `bat --help` to get a list of all possible configuration options.
+
+# Specify desired highlighting theme (e.g. "TwoDark"). Run `bat --list-themes`
+# for a list of all available themes
+# Custom theme lives in ./themes/ — run `bat cache --build` after changing it
+--theme="OneHalfDark"
+--style="numbers,changes,header,snip"
+
+# Enable this to use italic text on the terminal. This is not supported on all
+# terminal emulators (like tmux, by default):
+--italic-text=always
+
+# Uncomment the following line to disable automatic paging:
+#--paging=never
+
+# Uncomment the following line if you are using less version >= 551 and want to
+# enable mouse scrolling support in `bat` when running inside tmux. This might
+# disable text selection, unless you press shift.
+--pager="less --RAW-CONTROL-CHARS --quit-if-one-screen --mouse --ignore-case"
+
+# Syntax mappings: map a certain filename pattern to a language.
+#   Example 1: use the C++ syntax for Arduino .ino files
+#   Example 2: Use ".gitignore"-style highlighting for ".ignore" files
+--map-syntax "*.ino:C++"
+--map-syntax ".ignore:Git Ignore"
+--map-syntax "**/hypr/**/*.conf:INI"
+--map-syntax "**/kitty/*.conf:INI"
+--map-syntax "*.ctl:INI"
+--map-syntax ".inputrc:bash"
+--map-syntax "**/cava/config:INI"
+--map-syntax "**/mpv/*.conf:INI"
+--map-syntax "**/btop/btop.conf:INI"