Implement the selected Windows installer destination contract

[eimexdev]

Part of OpenBeat v0.1.0 public launch map.

Question

What installer, documentation, and test changes implement the contract selected by Choose the Windows installer destination contract?

Selected contract

• Default to %APPDATA%\Blackmagic Design\DaVinci Resolve\Support\Fusion.
• Support an editable Resolve Fusion support folder with a folder chooser.
• Explain that OpenBeat creates Scripts and Modules beneath the selected root.
• Keep the chosen root visible through confirmation and installation.
• Reject an empty root; allow creating a new folder.
• Do not attempt automatic discovery of relocated folders.

Minimum tests

• Default %APPDATA% resolution and fallback when it is absent.
• Chooser cancellation and empty-path rejection.
• Custom paths containing spaces and Unicode.
• Selected-root preservation through confirmation and installation.
• Scripts, modules, runtime, and generated Lua configuration placed beneath the selected root.
• Exact Windows artifact smoke coverage in the release checklist.

Completion signal

Installer behavior, generated Lua configuration, documentation, and tests all agree on default and custom destination handling.