[Sync] replace the flat layout with the unified stow tree

Supersedes the old flat .config/ layout (last published 2026-06-28) with the
private repo's structure: one shared base plus per-host overlays.

- packages: common/ gui/ lw/ fl/ wm/ plus install.sh and bin/ tooling
  (dotsync, reconcile-hyde.sh)
- new README covering the layout, deploy order and the HyDE dependency
- current HyDE waybar rig (layouts/, cava), pi agent extensions, claude/
  config, tmux, presenterm, aichat roles
- fish: kp (keepassxc-cli + fzf picker, db path from $KP_DB) and
  bind_M_n_history (alt+1..9 recalls the nth history entry)
- drops cruft that should never have been tracked: the duplicate top-level
  .pi/ copy, btop.log, zellij config.kdl.bak, fish_variables
- .pi/agent/auth.json is gitignored; auth.json.example ships instead

Host-specific work sessions and the personal backlog stay in the private
tree. Endpoint locators in the llamacpp/whisper guides are placeholders
($SERVER, <own-domain>) — the guides themselves stay, since they are the
useful part.

gui/.config/waybar/modules/workspaces.jsonc

@@ -0,0 +1,13 @@
+    "hyprland/workspaces": {
+        "disable-scroll": true,
+        "rotate": ${r_deg},
+        "all-outputs": true,
+        "active-only": false,
+        "on-click": "activate",
+        "disable-scroll": false,
+        "on-scroll-up": "hyprctl dispatch workspace -1",
+        "on-scroll-down": "hyprctl dispatch workspace +1",
+        "persistent-workspaces": {
+        }
+    },
+