[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.

common/.config/tmux/scripts/cpu.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+# CPU utilisation (%) averaged over the interval since the PREVIOUS status refresh:
+# /proc/stat totals persist in a state file between runs (same pattern as net.sh),
+# so the value covers the whole status-interval. (The old version slept 0.3s and
+# sampled just that window — a 6% duty cycle that aliased bursty loads.) No sleep,
+# ~5ms. First run (no state yet) shows the since-boot average. Glyph = Waybar's
+# cpu module icon (U+F035B).
+printf '\U000f035b '
+rt="${XDG_RUNTIME_DIR:-/tmp}"
+st="$rt/tmux_cpu_stat"   # previous totals:  tot idle
+
+read -r _ u n s i w rest < /proc/stat
+idle=$((i + w)); tot=$((u + n + s + i + w)); for v in $rest; do tot=$((tot + v)); done
+
+p_tot=0; p_idle=0
+[ -r "$st" ] && read -r p_tot p_idle < "$st"
+[ "$p_tot" -gt "$tot" ] && { p_tot=0; p_idle=0; }   # stale state from a previous boot
+printf '%s %s\n' "$tot" "$idle" > "$st"
+
+dt=$((tot - p_tot)); di=$((idle - p_idle))
+if [ "$dt" -le 0 ]; then printf -- '--%%'; else printf '%d%%' $(((100 * (dt - di) + dt / 2) / dt)); fi