[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/cava/shaders/bar_spectrum.frag

@@ -0,0 +1,79 @@
+#version 330
+
+in vec2 fragCoord;
+out vec4 fragColor;
+
+// bar values. defaults to left channels first (low to high), then right (high to low).
+uniform float bars[512];
+
+uniform int bars_count;    // number of bars (left + right) (configurable)
+uniform int bar_width;    // bar width (configurable), not used here
+uniform int bar_spacing;    // space bewteen bars (configurable)
+
+uniform vec3 u_resolution; // window resolution
+
+//colors, configurable in cava config file (r,g,b) (0.0 - 1.0)
+uniform vec3 bg_color; // background color
+uniform vec3 fg_color; // foreground color
+
+uniform int gradient_count;
+uniform vec3 gradient_colors[8]; // gradient colors
+
+vec3 normalize_C(float y,vec3 col_1, vec3 col_2, float y_min, float y_max)
+{
+    //create color based on fraction of this color and next color
+    float yr = (y - y_min) / (y_max - y_min);
+    return col_1 * (1.0 - yr) + col_2 * yr;
+}
+
+void main()
+{
+    // find which bar to use based on where we are on the x axis
+    float x = u_resolution.x * fragCoord.x;
+    int bar = int(bars_count * fragCoord.x);
+
+    //calculate a bar size
+    float bar_size = u_resolution.x / bars_count;
+
+    //the y coordinate and bar values are the same
+    float y =  bars[bar];
+
+    // make sure there is a thin line at bottom
+    if (y * u_resolution.y < 1.0)
+    {
+      y = 1.0 / u_resolution.y;
+    }
+
+    //draw the bar up to current height
+    if (y > fragCoord.y)
+    {
+        //make some space between bars basen on settings
+        if (x > (bar + 1) * (bar_size) - bar_spacing)
+        {
+            fragColor = vec4(bg_color,1.0);
+        }
+        else
+        {
+            if (gradient_count == 0)
+            {
+                fragColor = vec4(fg_color,1.0);
+            }
+            else
+            {
+                //find which color in the configured gradient we are at
+                int color = int((gradient_count - 1) * fragCoord.y);
+
+                //find where on y this and next color is supposed to be
+                float y_min = color / (gradient_count - 1.0);
+                float y_max = (color + 1.0) / (gradient_count - 1.0);
+
+                //make color
+                fragColor = vec4(normalize_C(fragCoord.y, gradient_colors[color], gradient_colors[color + 1], y_min, y_max), 1.0);
+            }
+        }
+    }
+    else
+    {
+        fragColor = vec4(bg_color,1.0);
+    }
+}