fix(ci): stop dd from corrupting the x86_64 linuxdeploy launcher

On the aarch64 Gitea runner, tauri-bundler's prepare_tools step runs
'dd ... seek=8 conv=notrunc' on the cached linuxdeploy-x86_64 binary to
hide it from AppImage integration tools. That zeroed bytes 8-10 of the
file; our cached binary there was a bash wrapper script, so the dd wrote
into the middle of its shebang/interpreter line, corrupting it, and the
bundler's subsequent spawn failed with ENOENT ('failed to bundle
project: No such file or directory').

Replace the shell wrapper with a small native ELF launcher compiled with
cc: bytes 8-10 of an ELF header are EI_PAD padding, unused by the
loader, so the same dd leaves it executable. The launcher sets the same
environment the old wrapper did and execs the real aarch64 linuxdeploy
binary. Also cache AppRun-x86_64 explicitly so the bundler does not need
to fetch it itself mid-build.

Verified locally: compiled a minimal ELF binary, ran the same dd
command against it, confirmed it still executes (the shebang-script
equivalent does not).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VAyr8d7HuAdUGB6aA5xmDD

scripts/generate-logo.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+"""Gera, a partir da logo oficial, o ícone base usado pelo Tauri.
+
+A logo oficial é `logo.png` na raiz do repositório (RGBA, fundo transparente,
+serve aos temas claro e escuro). Ela não é alterada aqui. Saída:
+  apps/gui/src-tauri/icons/source.png      1024 px, a arte sobre o fundo escuro com cantos arredondados;
+                                           o CI e `npx @tauri-apps/cli icon` geram o resto dos ícones.
+
+Uso: python3 scripts/gerar-logo.py
+"""
+import os
+from PIL import Image, ImageDraw
+
+RAIZ = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..")
+ICONES = os.path.join(RAIZ, "apps/gui/src-tauri/icons")
+FUNDO_ICONE = (10, 16, 28)  # o azul-noite do fundo da arte original
+
+
+def recortar_quadrado(im, margem=0.04):
+    """Recorta no que é visível (opacidade > 16, ignora resquícios) e centraliza num quadrado."""
+    box = im.getchannel("A").point(lambda v: 255 if v > 16 else 0).getbbox()
+    im = im.crop(box)
+    w, h = im.size
+    lado = round(max(w, h) * (1 + 2 * margem))
+    quadro = Image.new("RGBA", (lado, lado), (0, 0, 0, 0))
+    quadro.paste(im, ((lado - w) // 2, (lado - h) // 2), im)
+    return quadro
+
+
+def main():
+    logo = recortar_quadrado(Image.open(os.path.join(RAIZ, "logo.png")).convert("RGBA"))
+
+    lado = 1024
+    fundo = Image.new("RGBA", (lado, lado), FUNDO_ICONE + (255,))
+    arte = logo.resize((round(lado * 0.82),) * 2, Image.LANCZOS)
+    fundo.paste(arte, ((lado - arte.width) // 2, (lado - arte.height) // 2), arte)
+    mascara = Image.new("L", (lado, lado), 0)
+    ImageDraw.Draw(mascara).rounded_rectangle((0, 0, lado - 1, lado - 1), radius=round(lado * 0.2237), fill=255)
+    icone = Image.new("RGBA", (lado, lado), (0, 0, 0, 0))
+    icone.paste(fundo, (0, 0), mascara)
+    os.makedirs(ICONES, exist_ok=True)
+    destino = os.path.join(ICONES, "source.png")
+    icone.save(destino, optimize=True)
+    os.chmod(destino, 0o644)
+    print("icons/source.png")
+
+
+if __name__ == "__main__":
+    main()