Fix rounded macOS icon on older Macs (#8018)

Older macOS versions display Buzz’s opaque icon as an oversized square.
Bake rounded corners and transparent padding into the macOS `.icns`,
preserving the original bee artwork and leaving other platforms
unchanged.

Generation uses Hermit-pinned uv, Python 3.14.3, and Pillow 12.2.0.
`scripts/macos-icon.sh --check` regenerates temporarily and compares all
decoded representations; macOS CI runs it before packaging. Pixel
reproducibility is verified independently of Apple’s ICNS container
encoding.

Validated native AppKit preview, all 10 representations, fresh-cache
generation, one-pixel/missing-representation drift rejection, workflow
lint, and pre-push checks. Full local `just ci` is running. Packaged
Dock checks on older/current macOS remain outstanding.

---------

Signed-off-by: kenny lopez <klopez4212@gmail.com>

scripts/generate-macos-icon.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+"""Build the legacy macOS icon without relying on system corner masking.
+
+Run: scripts/macos-icon.sh [--check]
+
+The wrapper pins uv, Python and Pillow. Verification compares the complete set
+of decoded RGBA representations, not PNG encoding or ICNS container bytes:
+Apple's system iconutil may encode the same pixels differently across macOS.
+The shared artwork and other platforms' icons are intentionally untouched.
+"""
+
+# /// script
+# requires-python = "==3.14.3"
+# dependencies = ["Pillow==12.2.0"]
+# ///
+
+import argparse
+from pathlib import Path
+import subprocess
+import tempfile
+
+from PIL import Image, ImageDraw
+
+
+ROOT = Path(__file__).resolve().parent.parent
+ICONS = ROOT / "desktop/src-tauri/icons"
+
+
+def generate(output):
+    # An 824px tile on a 1024px canvas leaves the macOS optical inset.
+    # Work at 4x resolution to antialias the rounded edge at every icon size.
+    scale = 4
+    canvas = Image.new("RGBA", (1024 * scale, 1024 * scale))
+    with Image.open(ICONS / "buzz-source.png") as source:
+        tile = source.convert("RGBA").resize(
+            (824 * scale, 824 * scale), Image.Resampling.LANCZOS
+        )
+    mask = Image.new("L", tile.size)
+    ImageDraw.Draw(mask).rounded_rectangle(
+        (0, 0, tile.width - 1, tile.height - 1), radius=185 * scale, fill=255
+    )
+    canvas.paste(tile, (100 * scale, 100 * scale), mask)
+
+    with tempfile.TemporaryDirectory(prefix="buzz-macos-icon-") as temporary:
+        iconset = Path(temporary) / "Buzz.iconset"
+        iconset.mkdir()
+        for size in (16, 32, 128, 256, 512):
+            for density in (1, 2):
+                suffix = "@2x" if density == 2 else ""
+                canvas.resize(
+                    (size * density, size * density), Image.Resampling.LANCZOS
+                ).save(iconset / f"icon_{size}x{size}{suffix}.png")
+        subprocess.run(
+            ["/usr/bin/iconutil", "-c", "icns", str(iconset), "-o", str(output)],
+            check=True,
+        )
+
+
+def verify(candidate, reference):
+    """Reject missing/extra representations and any decoded pixel drift."""
+    with tempfile.TemporaryDirectory(prefix="buzz-icon-check-") as temporary:
+        sets = []
+        for name, icon in (("candidate", candidate), ("reference", reference)):
+            iconset = Path(temporary) / f"{name}.iconset"
+            subprocess.run(
+                ["/usr/bin/iconutil", "-c", "iconset", str(icon), "-o", str(iconset)],
+                check=True,
+            )
+            sets.append({p.name: p for p in iconset.glob("*.png")})
+        if sets[0].keys() != sets[1].keys():
+            raise ValueError("macOS icon representation set drifted")
+        for name in sorted(sets[0]):
+            with Image.open(sets[0][name]) as a, Image.open(sets[1][name]) as b:
+                if a.size != b.size or a.convert("RGBA").tobytes() != b.convert("RGBA").tobytes():
+                    raise ValueError(f"macOS icon pixel drift: {name}")
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--check", action="store_true", help="verify without modifying the icon")
+    parser.add_argument("--output", type=Path, default=ICONS / "icon.icns")
+    args = parser.parse_args()
+    if args.check:
+        with tempfile.TemporaryDirectory(prefix="buzz-icon-regenerate-") as temporary:
+            generated = Path(temporary) / "icon.icns"
+            generate(generated)
+            verify(args.output, generated)
+        print("macOS icon: all decoded representations match")
+    else:
+        generate(args.output)
+
+
+if __name__ == "__main__":
+    main()

scripts/macos-icon.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+# Hermit pins uv; inline script metadata pins Python and Pillow exactly.
+# uv script environments are isolated from the caller's Python packages.
+exec "$ROOT/bin/uv" run --managed-python --python 3.14.3 \
+  --script "$ROOT/scripts/generate-macos-icon.py" "$@"