[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/pulseaudio.jsonc

@@ -0,0 +1,35 @@
+"pulseaudio": {
+    "format": "{icon} {volume}",
+    "rotate": ${r_deg},
+    "format-muted": "婢",
+    "on-click": "pavucontrol -t 3",
+    "on-click-right": "volumecontrol.sh -s ''",
+    "on-click-middle": "volumecontrol.sh -o m",
+    "on-scroll-up": "volumecontrol.sh -o i",
+    "on-scroll-down": "volumecontrol.sh -o d",
+    "tooltip-format": "{icon} {desc} // {volume}%",
+    "scroll-step": 5,
+    "format-icons": {
+        "headphone": "",
+        "hands-free": "",
+        "headset": "",
+        "phone": "",
+        "portable": "",
+        "car": "",
+        "default": ["", "", ""]
+    }
+},
+
+"pulseaudio#microphone": {
+    "format": "{format_source}",
+    "rotate": ${r_deg},
+    "format-source": "",
+    "format-source-muted": "",
+    "on-click": "pavucontrol -t 4",
+    "on-click-middle": "volumecontrol.sh -i m",
+    "on-scroll-up": "volumecontrol.sh -i i",
+    "on-scroll-down": "volumecontrol.sh -i d",
+    "tooltip-format": "{format_source} {source_desc} // {source_volume}%",
+    "scroll-step": 5
+},
+