docs: close out Milestone 9 and document Windows/macOS packaging

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -13,8 +13,8 @@ Supported target platforms:
 
 OrbitHub is in active development.
 
-- Milestones completed: M0-M5, M7, and M8
-- Current milestone: Milestone 9 (Packaging and Distribution)
+- Milestones completed: M0-M5, and M7-M9
+- Current milestone: Milestone 10 (v1.0 Stabilization)
 - Deferred milestone: Milestone 6 (VNC Fully Working)
 - Latest checkpoint tag: `v0-m8-done`
 - VNC implementation milestone (M6) is currently deferred
@@ -90,18 +90,35 @@ cmake --build build
 ./build/orbithub
 ```
 
-## Packaging (Linux)
+## Packaging
+
+Detailed packaging instructions for all platforms:
+- [docs/BUILDING.md](docs/BUILDING.md)
+
+Linux (`.deb`):
 
 ```bash
 ./packaging/linux/build-deb.sh
 ```
 
-Optional Flatpak bundle:
+Linux (Flatpak):
 
 ```bash
 ./packaging/flatpak/build-flatpak.sh
 ```
 
+Windows (Inno Setup installer):
+
+```powershell
+.\packaging\windows\build-installer.ps1
+```
+
+macOS (`.dmg`):
+
+```bash
+./packaging/macos/build-dmg.sh
+```
+
 ## Dependencies
 
 Core dependencies: