chore(branding): point firmware at wevisto.com

Flip APP_BASE_URL and the on-screen "go to <domain>/setup/..." text in
the rendered setup_bg images from pictureframe.edholm.me to wevisto.com.
Per the dual-domain migration plan (Option C — server keeps both alive
indefinitely), this only affects newly-flashed units; field devices on
the old URL keep working against the same backend.

Regenerated both panels' setup_bg.bin via gen_screens*.py so the
embedded URL in the on-screen QR overlay text matches the firmware's
runtime poll URL.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/config.h

@@ -126,7 +126,7 @@
 #define BORDER_THICKNESS_PX 4
 
 // ── Network ──────────────────────────────────────────────────────────────
-#define APP_BASE_URL      "https://pictureframe.edholm.me"
+#define APP_BASE_URL      "https://wevisto.com"
 #define AP_IP             "192.168.4.1"
 // AP security — WPA2-PSK with a fixed password baked into both the
 // firmware and the WIFI: QR. Open networks have flakier iOS captive-