[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)

wm/.config/hypr/nvidia.conf

@@ -0,0 +1,30 @@
+
+# █▄░█ █░█ █ █▀▄ █ ▄▀█
+# █░▀█ ▀▄▀ █ █▄▀ █ █▀█
+
+# Hyprland Nvidia Configuration
+# See https://wiki.hyprland.org/Nvidia/
+env = LIBVA_DRIVER_NAME,nvidia
+env = __GLX_VENDOR_LIBRARY_NAME,nvidia # Disable this if you have issues with screensharing
+
+
+# If you want to try hardware cursors,
+# you can enable them by setting `cursor:no_hardware_cursors = false` ,
+# but it will require also enabling `cursor:allow_dumb_copy`
+# which may cause small to major hitches whenever the cursor shape changes.
+# If this is a problem on your system, keep hardware cursors disabled.
+cursor:no_hardware_cursors = true # Set to true to avoid hitches
+# cursor:allow_dumb_copy = true
+
+# https://wiki.hyprland.org/Nvidia/#va-api-hardware-video-acceleration
+# Hardware video acceleration on Nvidia and Wayland is
+# possible with the nvidia-vaapi-driver.
+# This may solve specific issues in Electron apps.
+env = NVD_BACKEND,direct # Requires 'libva-nvidia-driver' package
+
+# https://wiki.hyprland.org/Nvidia/#regarding-environment-variables
+# If you encounter crashes in Firefox, remove this line
+env = GBM_BACKEND,nvidia-drm
+
+# If you have a multi-GPU setup and you are facing lag in external monitor.
+# See https://wiki.hyprland.org/Configuring/Multi-GPU/