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>

flake.lock

@@ -215,11 +215,11 @@
     "nomarchy-wallpapers": {
       "flake": false,
       "locked": {
-        "lastModified": 1784302860,
-        "narHash": "sha256-nQ+eLEggLxDcbKks3Ui6rbJ4P24H2JXenLLg9si007M=",
+        "lastModified": 1784374559,
+        "narHash": "sha256-c05z+PUFbX3gZ7CQfFHtVCWI5WlNCAcFQBC/bBv7G+Y=",
         "ref": "main",
-        "rev": "803b48ddf35aeff08999c8c7f563457181105cf5",
-        "revCount": 2,
+        "rev": "a716cf60a05f187ad1d8baa043dda4e6085c2463",
+        "revCount": 3,
         "type": "git",
         "url": "https://git.bemagri.xyz/bernardo/Nomarchy-Wallpapers.git"
       },