docs: define MSIX-first packaging design and roadmap

Document package formats, release workflows, deployment planning and UI concepts.

Closes #1

docs/code-design/examples/generic.package-project.json

@@ -0,0 +1,36 @@
+{
+  "schemaVersion": 2,
+  "product": {
+    "displayName": "Sample Desktop Tool",
+    "manufacturer": "Example Publisher",
+    "displayVersion": "1.0.0"
+  },
+  "sources": [{ "alias": "appPayload" }],
+  "files": [{ "id": "application", "source": "appPayload", "include": ["**/*"], "exclude": [], "targetRelativePath": "", "required": true }],
+  "formats": {
+    "exe": {
+      "msiVersion": "1.0.0",
+      "architecture": "x64",
+      "upgradeCode": null,
+      "installScope": "perMachine",
+      "installRoot": "[ProgramFiles64Folder]ExamplePublisher\\SampleDesktopTool",
+      "registry": [],
+      "prerequisites": [],
+      "patchPolicy": { "enabled": true },
+      "installationFlow": { "template": "standard" },
+      "installerUi": { "template": "standard-wizard" }
+    },
+    "msix": {
+      "identity": { "name": "ExamplePublisher.SampleDesktopTool", "publisher": null, "version": "1.0.0.0", "architecture": "x64" },
+      "minimumOsVersion": "10.0.19041.0",
+      "applications": [{ "id": "App", "executable": "SampleTool.exe", "entryPoint": "Windows.FullTrustApplication", "square44x44Logo": "Assets/Logo44.png", "square150x150Logo": "Assets/Logo150.png" }],
+      "capabilities": ["runFullTrust"],
+      "extensions": [],
+      "dependencies": []
+    }
+  },
+  "targets": [
+    { "id": "exe-direct", "format": "exe", "delivery": "offline-singlefile", "distribution": "direct", "signingProfileRef": null },
+    { "id": "msix-direct", "format": "msix", "delivery": "package", "distribution": "direct", "signingProfileRef": null }
+  ]
+}