[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)

.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