v2.63.2 — Claude Desktop MSIX config path fix (Windows)

Installer fix for Windows MSIX builds of Claude Desktop (#93, reported by @corolorn). No tool-surface change.

Fixed

• Installer writes Claude Desktop config to the MSIX-virtualized path on Windows — Claude Desktop for Windows ships as an MSIX package (even when downloaded from the official website, not the Microsoft Store). MSIX filesystem virtualization redirects the app's config to
  %LOCALAPPDATA%\Packages\Claude_<publisherhash>\LocalCache\Roaming\Claude\claude_desktop_config.json,
  and the app never reads the documented %APPDATA%\Claude\ path — so the installer's config entry silently never appeared in the app. The installer now detects the containerized path (publisher hash globbed, not hard-coded) and writes there when present, falling back to %APPDATA%\Claude\ for non-MSIX installs. A Claude_* package directory whose app has never been launched (no LocalCache\Roaming\Claude yet) does not divert the config.
• Documented both locations and the MSIX gotcha in docs/install.md.

Tests

• 4 new unit tests covering MSIX-path preference, the non-MSIX fallback, the never-launched-package case, and the registered client entry on Windows. Full suite: 1527 passed.