[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)

lw/.config/xremap/config.yml

@@ -0,0 +1,40 @@
+# F13 is a real keycode that no app binds. We declare it a virtual modifier so it can
+# prefix the nav-layer chords below, then remap RightAlt -> F13 (see modmap). This mirrors
+# the wm/fl evremap setup: RightAlt only ever emits F13, so a bare tap/hold never triggers
+# app menu bars and no stray Alt leaks on unmapped chords.
+virtual_modifiers:
+  - F13
+
+modmap:
+  - name: CapsLock to LeftCtrl/Esc
+    remap:
+      CapsLock:
+        held: leftctrl
+        alone: esc
+        alone_timeout_millis: 150
+
+  - name: RightAlt to F13 (nav-layer modifier; Left Alt untouched)
+    remap:
+      Alt_R: F13
+
+keymap:
+  - name: RightAlt(F13) vim-nav layer — mirrors wm/fl evremap
+    remap:
+      F13-h: left
+      F13-j: down
+      F13-k: up
+      F13-l: right
+      F13-u: pageup
+      F13-d: pagedown
+      F13-b: C-left      # word left  (Ctrl+Left)
+      F13-w: C-right     # word right (Ctrl+Right)
+
+# keymap:
+#   - name: Freetube remap
+#     application:
+#       only: FreeTube
+#     remap:
+#       Alt-h: Left
+#       Alt-l: Right
+#       Alt-j: Down
+#       Alt-k: Up