feat(themes): boreal-dawn — the light half of the boreal day/night pair

First of three Nomarchy-exclusive dark/light pairs for v1 (with
executive-ivory and kiln/kiln-clay in the next commits), built for
settings.autoTheme: same identity in two lights, so the sunrise flip
feels like the same room brightening.

Boreal Dawn is the boreal forest six hours later — the aurora faded
into a cold clear dawn. Frost-paper base (#EDF2F6), deep-slate text
(10.9:1 AAA), the aurora violet deepened to text-grade (#7458C8,
4.69:1), spruce teal accentAlt (#22766E), GeistMono + the same 6/14/3/12
geometry as boreal so the pair swaps shape-invariant. Assets: whole-swap
waybar (the same three frosted pills, light glass), rofi + 4x3 launcher
grid, btop theme, dawn-treeline wallpaper mirroring aurora-boreal's
composition (same spiky silhouette, dawn gradient, fading stars).

flake.lock: nomarchy-wallpapers 803b48d -> a716cf6 — the single-input
bump carrying backgrounds for all four new slugs (this task is the lock
bump). Preview is a real render: theme-shot VM desktop at 480x270.

Verification: V2. nix flake check --no-build green; checks
theme-contrast (28x7+chips), theme-wholeswap, waybar-language,
waybar-swap-env, rofi-text-width, state-sync-validate, auto-theme (VM
day/night engine) all green. Visual protocol: theme-shot VM renders
viewed for desktop + menu (frosted pills, wash selection, legibility —
screenshots in /nix/store/l26kfdcf...theme-shot-boreal-dawn). audit
findings at/below the boreal baseline (CVD-only + the same
accent-pair Δhue as boreal). V3 pending: real-GL blur, btop visual,
launcher grid on hardware (HARDWARE-QUEUE, this batch's entry).

Design by Fable (palette lab + wallpaper SVGs); asset port by a Sonnet
subagent from the boreal sources; reviewed file-by-file on Fable.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

themes/boreal-dawn/launcher.rasi

@@ -0,0 +1,42 @@
+/**
+ * Boreal Dawn — app-launcher override (themes/<slug>/launcher.rasi).
+ * Installed to ~/.local/share/rofi/themes/launcher.rasi and used only by
+ * `rofi -show drun` (the SUPER+Space / SUPER+D launcher). It inherits the
+ * frosted dawn panel from the sibling rofi.rasi (this whole-swap theme,
+ * which HM deploys under its source basename — rofi.rasi — not custom.rasi),
+ * then reshapes the list into a 4×3 grid of large application icons.
+ * Text menus keep the list — they don't use this theme.
+ */
+
+@import "rofi.rasi"
+
+window { width: 780px; }
+
+listview {
+    columns: 4;
+    lines: 3;
+    fixed-columns: true;
+    spacing: 10px;
+    padding: 6px 0px 0px 0px;
+    /* Fill row-by-row so Down at a column's foot pages to the next screen
+       instead of jumping to the top of the next column (rofi's default
+       Vertical flow). Mirrors the theme-picker grid in rofi.nix. */
+    flow: horizontal;
+}
+
+element {
+    orientation: vertical;
+    padding: 16px 8px;
+    spacing: 10px;
+    border-radius: 12px;
+}
+
+element-icon {
+    size: 56px;
+    horizontal-align: 0.5;
+}
+
+element-text {
+    horizontal-align: 0.5;
+    vertical-align: 0.5;
+}