feat(themes): per-theme rofi identities for nord/retro-82/lumon/kanagawa

Author a designed rofi.rasi whole-swap for the four remaining identity
themes, so all six now carry a distinct menu look (summer-day/night
already shipped their legacy ports). Each is built from the theme's
character rather than a legacy layout (their waybar overrides are
palette-only, so there was nothing to port):

- nord:     soft rounded "frost panel" — frost border, brighter-frost
            selection, aurora-purple prompt
- retro-82: sharp CRT terminal — square corners, amber-on-navy, a teal
            scanline underline, mono
- lumon:    clinical cyan "bezel" — thick cyan frame, a framed-not-filled
            readout inputbar, mono
- kanagawa: ink & paper — warm washi-paper frame, deep ink-well inputbar,
            crystal-blue wave selection

Each file is self-contained (it replaces the generated theme) and keeps
the element structure the theme-grid picker's per-invocation -theme-str
layers onto. rofi.nix needs no change — its existing themes/<slug>/
rofi.rasi probe whole-swaps when the file is present. All four parse
clean under `rofi -dump-theme`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

themes/kanagawa/rofi.rasi

@@ -0,0 +1,107 @@
+/**
+ * Nomarchy Kanagawa — rofi whole-swap (themes/<slug>/rofi.rasi).
+ * Ink-and-paper identity: a sumi-ink canvas inside a warm washi-paper frame
+ * (the same text-toned border the theme uses on windows — the only warm
+ * frame of the four), the inputbar a deeper ink well, and the crystal-blue
+ * wave reserved for the selected row. Soft rounding, an unhurried feel.
+ * The `configuration {}` block is omitted on purpose — modi/terminal/
+ * show-icons come from modules/home/rofi.nix.
+ */
+
+* {
+    sumi:   #1f1f28;  /* sumi ink — the canvas               */
+    well:   #090618;  /* deeper ink — inputbar + zebra       */
+    paper:  #dcd7ba;  /* washi paper — text + frame          */
+    parch:  #c8c093;  /* parchment — the prompt              */
+    grey:   #727169;
+    wave:   #7e9cd8;  /* crystal-blue wave — the selection   */
+
+    font: "JetBrainsMono Nerd Font 14";
+    background-color: transparent;
+    text-color: @paper;
+}
+
+window {
+    background-color: @sumi;
+    border: 2px;
+    border-color: @paper;      /* the warm paper frame (kanagawa's border tone) */
+    border-radius: 10px;
+    width: 40%;
+    location: center;
+    anchor: center;
+    padding: 8px;
+}
+
+mainbox {
+    background-color: transparent;
+    children: [ inputbar, message, listview ];
+    spacing: 0px;
+}
+
+inputbar {
+    children: [ prompt, entry ];
+    background-color: @well;    /* the ink well */
+    text-color: @paper;
+    border-radius: 8px;
+    padding: 10px 12px;
+    spacing: 8px;
+    margin: 0px 0px 8px 0px;
+}
+
+prompt { text-color: @parch; }
+
+entry {
+    text-color: @paper;
+    cursor: text;
+    placeholder: "search…";
+    placeholder-color: @grey;
+}
+
+listview {
+    background-color: transparent;
+    columns: 1;
+    lines: 8;
+    dynamic: true;
+    scrollbar: false;
+    spacing: 4px;
+    padding: 8px 0px 0px 0px;
+}
+
+element {
+    background-color: transparent;
+    text-color: @paper;
+    orientation: horizontal;
+    border-radius: 8px;
+    padding: 10px 14px;
+    spacing: 12px;
+}
+
+element alternate.normal {
+    background-color: @well;
+}
+element selected.normal {
+    background-color: @wave;
+    text-color: @sumi;
+}
+
+element-icon {
+    background-color: transparent;
+    size: 36px;
+    cursor: inherit;
+}
+element-text {
+    background-color: transparent;
+    text-color: inherit;
+    highlight: bold;
+    vertical-align: 0.5;
+}
+
+message { padding: 8px 0px 0px 0px; }
+textbox {
+    background-color: @well;
+    text-color: @paper;
+    border-radius: 8px;
+    padding: 8px 12px;
+}
+
+scrollbar { width: 0px; }