[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)

common/.config/tmux/scripts/temp.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+# CPU temperature (°C) for the tmux status bar (thermometer glyph U+F050F).
+# Sensor hunt, most→least specific: a CPU-ish thermal zone (x86_pkg_temp/…),
+# else a CPU hwmon chip (coretemp/k10temp/…), else the hottest remaining zone
+# (acpitz can be a bogus constant on desktops, hence last). Prints NOTHING when
+# no sensor exists (VMs/containers) so the segment simply disappears — which is
+# also why the trailing spacing lives in here, not in status-right.
+cpu_zone=""; any_zone=""; hw=""
+
+for d in /sys/class/thermal/thermal_zone*/; do
+  [ -r "${d}temp" ] && [ -r "${d}type" ] || continue
+  t=$(<"${d}temp")
+  case $t in ''|*[!0-9]*) continue ;; esac
+  ty=$(<"${d}type"); ty=${ty,,}
+  case $ty in *x86_pkg_temp*|*coretemp*|*k10temp*|*tctl*|*cpu*)
+    if [ -z "$cpu_zone" ] || [ "$t" -gt "$cpu_zone" ]; then cpu_zone=$t; fi ;;
+  esac
+  if [ -z "$any_zone" ] || [ "$t" -gt "$any_zone" ]; then any_zone=$t; fi
+done
+
+if [ -z "$cpu_zone" ]; then
+  for d in /sys/class/hwmon/hwmon*/; do
+    [ -r "${d}name" ] || continue
+    case $(<"${d}name") in coretemp|k10temp|zenpower|cpu_thermal)
+      for f in "${d}"temp*_input; do
+        [ -r "$f" ] || continue
+        t=$(<"$f")
+        case $t in ''|*[!0-9]*) continue ;; esac
+        if [ -z "$hw" ] || [ "$t" -gt "$hw" ]; then hw=$t; fi
+      done ;;
+    esac
+  done
+fi
+
+t=${cpu_zone:-${hw:-$any_zone}}
+[ -n "$t" ] || exit 0
+printf '\U000f050f %d°  ' $(( (t + 500) / 1000 ))