[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/fish/functions/opencodes.fish

@@ -0,0 +1,24 @@
+function opencodes --description 'contained opencode' 
+  bwrap \
+    --unshare-all \
+    --new-session \
+    --clearenv \
+    --die-with-parent \
+    --share-net \
+    --dev /dev \
+    --proc /proc \
+    --ro-bind /usr /usr \
+    --ro-bind /lib /lib \
+    --ro-bind /lib64 /lib64 \
+    --ro-bind /bin /bin \
+    --ro-bind /etc /etc \
+    --ro-bind ~/.config/opencode ~/.config/opencode \
+    --tmpfs /tmp/node-compile-cache \
+    --bind ~/.local/state/opencode ~/.local/state/opencode \
+    --bind ~/.local/share/opencode ~/.local/share/opencode \
+    --bind "$(pwd)" "$(pwd)" \
+  opencode
+end
+
+
+