[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.

.gitignore

@@ -1,3 +1,34 @@
-!.gitignore
-.config/hyde/themes/
-.config/fish/greet.txt
+# Secrets / local-only (matched at any depth)
+secrets.fish
+fish_variables
+greet.txt
+settings.local.json
+
+# pi agent runtime + machine-local auth/state
+**/.pi/agent/auth.json
+**/.pi/agent/sessions/
+**/.pi/agent/bin/
+**/.pi/agent/git/
+**/.pi/agent/npm/
+**/.pi/agent/trust.json
+
+# tmux plugins (tpm-managed, not vendored)
+**/tmux/plugins/
+
+# HyDE generated theme + wallpaper assets (per-machine, huge — bloated the old repo to 255MB)
+**/hyde/themes/
+**/wallpapers/
+
+# Claude Code project dir (worktrees, local settings, history) — never part of the dotfiles
+.claude/
+
+# backups / logs / package noise / os
+*.bak
+*.bak.*
+*.log
+package-lock.json
+__pycache__/
+**/hypr/themes/
+# HyDE writes these at theme-apply time (sourced by animations/theme.conf & hyprlock/theme.conf)
+**/hypr/animations/HyDE.conf
+**/hypr/hyprlock/HyDE.conf