Add per-user MSI installer for Windows; strip Mark-of-the-Web in frozen ZIP builds

Files extracted from a downloaded ZIP carry a Zone.Identifier stream and the
.NET Framework CLR refuses to load such assemblies, so pythonnet failed with
'Failed to resolve Python.Runtime.Loader.Initialize'. MSI-installed files have
no MOTW; the winmain strip fixes the ZIP distribution.

scripts/release.py

@@ -67,13 +67,14 @@ def load_token() -> str:
 # ZIP + dist helpers
 # ---------------------------------------------------------------------------
 
-# Matches MediaHive-1.2.3-win64.zip, MediaHive-1.2.3-macos-arm64.dmg, etc.
+# Matches MediaHive-1.2.3-win64.zip, MediaHive-1.2.3-win64.msi,
+# MediaHive-1.2.3-macos-arm64.dmg, etc.
 # Rejects dev/dirty versions like MediaHive-1.2.3.dev0+gabcd-win64.zip
-_CLEAN_ARTIFACT_RE = re.compile(r"^MediaHive-(\d+(?:\.\d+)*)-([A-Za-z0-9._-]+)\.(?:zip|dmg)$")
+_CLEAN_ARTIFACT_RE = re.compile(r"^MediaHive-(\d+(?:\.\d+)*)-([A-Za-z0-9._-]+)\.(?:zip|dmg|msi)$")
 
 
 def find_releasable_artifacts() -> list[tuple[Path, str, str]]:
-    """Return (path, version, platform_tag) for clean-versioned ZIPs/DMGs in build/."""
+    """Return (path, version, platform_tag) for clean-versioned ZIPs/DMGs/MSIs in build/."""
     build_dir = REPO_ROOT / "build"
     results = []
     for p in sorted(build_dir.glob("MediaHive-*")):
@@ -183,6 +184,7 @@ def upload_asset(
     mime = {
         ".zip": "application/zip",
         ".dmg": "application/x-apple-diskimage",
+        ".msi": "application/x-msi",
     }.get(path.suffix, "application/octet-stream")
     print(f"Uploading {path.name} ({size_mb:.1f} MB) ...")
     with Path(path).open("rb") as fh:
@@ -228,7 +230,7 @@ def main() -> None:
         artifacts = find_releasable_artifacts()
         if not artifacts:
             print(
-                "No clean-versioned ZIPs/DMGs found in build/.\n"
+                "No clean-versioned ZIPs/DMGs/MSIs found in build/.\n"
                 "Run scripts/guibuild.py first.",
                 file=sys.stderr,
             )