[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/network.jsonc

@@ -0,0 +1,13 @@
+    "network": {
+        "tooltip": true,
+        "format-wifi": " ",
+        "rotate": ${r_deg},
+        "format-ethernet": "󰈀 ",
+        "tooltip-format": "Network: <big><b>{essid}</b></big>\nSignal strength: <b>{signaldBm}dBm ({signalStrength}%)</b>\nFrequency: <b>{frequency}MHz</b>\nInterface: <b>{ifname}</b>\nIP: <b>{ipaddr}/{cidr}</b>\nGateway: <b>{gwaddr}</b>\nNetmask: <b>{netmask}</b>",
+        "format-linked": "󰈀 {ifname} (No IP)",
+        "format-disconnected": "󰖪 ",
+        "tooltip-format-disconnected": "Disconnected",
+        "format-alt": "<span foreground='#99ffdd'> {bandwidthDownBytes}</span> <span foreground='#ffcc66'> {bandwidthUpBytes}</span>",
+        "interval": 2
+    }
+