release: a portable zip replaces the Windows MSI

[Shman4ik]

What and why

The direct Windows download becomes a portable pgNimbus-<version>-win-x64.zip instead of a per-user MSI.

• Nobody downloads the MSI. About 38 downloads across 30 releases, and none for 0.13.0, 0.13.1 or 1.0.0. Windows users come through the Microsoft Store, and winget install pgNimbus resolves to the Store package too.
• It had started to cost more. WiX 7 refuses to build until its OSMF EULA is accepted (WIX7015, found while checking Bump wix from 5.0.2 to 7.0.0 #305), so the MSI meant a build dependency and a licence for a channel nobody used. Bump wix from 5.0.2 to 7.0.0 #305 and build(deps): WiX 7, with its OSMF EULA accepted for the MSI build #341 are closed in favour of this PR.
• What the zip gives up: the Start menu shortcut, the Apps entry, and upgrading in place. The app keeps its data in %AppData%\pgNimbus either way, so updating means replacing the folder. The app has no update check, so an MSI user was already downloading every version by hand.

Changes

• release.yml. WiX restore, Build MSI and the msiexec install/uninstall smoke are gone. In their place:
  • scripts/windows/build-zip.ps1 packs one top-level folder (pgNimbus-<version>-win-x64/, like the Linux .tar.gz) with no .pdb;
  • a smoke step unpacks the zip into a fresh folder, launches the exe and fails if a .pdb shipped;
  • the SHA, the windows-zip artifact, the release download pattern and the checksum/upload globs follow.
• winget manifests describe a zip with a nested portable exe aliased pgnimbus. ArchiveBinariesDependOnPath puts the folder on PATH, because a symlinked exe would be cut off from the native DLLs next to it. The templates move to schema 1.9.0 (the field doesn't exist in 1.6.0) and carry schema headers. Scope is dropped, since it doesn't apply to portable.
• WiX leaves .config/dotnet-tools.json, and packaging/windows/Product.wxs is deleted.
• Docs:
  • README, the installation guide (with a note telling MSI users to uninstall and move to the Store or the zip), docs/index.md and the landing page;
  • the bug template's install-method list, which also gains the Store and the three Linux packages it never had;
  • release-ci.md, logo-assets.md, LOGO-ASSETS.md, CLAUDE.md's layout line, the release checklist's caveats, ROADMAP T5, and the script comments that pointed at Product.wxs.

Verified

• build-zip.ps1 over a local win-x64 publish: a 52 MB zip (JIT self-contained; the AOT one will be smaller) with one top-level folder and no .pdb (the publish had 3).
• Unpacked and launched with Smoke-Launch.ps1 (PGNIMBUS_DATA_DIR set to a scratch folder): PGNIMBUS_STARTUP_PROBE window_ms=2085, ok.
• render-manifest.sh + winget validate (winget 1.30 preview): Manifest validation succeeded, no warnings. The 1.6.0 schema warned Unknown field [ArchiveBinariesDependOnPath].
• Not run: the release workflow itself (workflow_dispatch), so the zip steps haven't run on a GitHub runner yet, with that runner's winget validating 1.9.0. Worth one dispatch before the next tag.
• Not run: winget install --manifest (it needs the local-manifest admin setting enabled on this machine).

No app code, no UI change, nothing in shared/nimbusUi.

🤖 Generated with Claude Code