docs(desktop): document local Windows installer builds

.agents/skills/windows-desktop-build/SKILL.md

@@ -0,0 +1,20 @@
+---
+name: windows-desktop-build
+description: "Build or package the Buzz Tauri desktop app on Windows. Use when: asked to build the Windows desktop executable, MSI, NSIS installer, run pnpm tauri build on Windows, prepare Tauri externalBin sidecars, fix missing target-qualified sidecar errors, or diagnose a locked buzz-desktop.exe during packaging."
+---
+
+# Windows Desktop Build
+
+Use the repository's human-maintained build procedure in
+[`desktop/README.md`](../../../desktop/README.md#build-windows-installers-locally).
+
+Key constraints:
+
+- Run native `cargo`, `pnpm`, and PowerShell commands on Windows; do not invoke
+  the Unix wrappers under `bin/`.
+- Build and copy all five release sidecars before invoking Tauri.
+- Stop a running `buzz-desktop.exe` before rebuilding to avoid Windows file
+  locking.
+- Use `pnpm -C desktop tauri build` for the final package. It runs the frontend
+  build and emits MSI and NSIS installers; do not add a separate frontend build
+  or temporary Tauri configuration.

desktop/README.md

@@ -18,6 +18,153 @@ Desktop chat shell with:
 - `pnpm format` - Biome format (write)
 - `pnpm check` - Biome check
 
+## Prepare a Windows development host
+
+Buzz's checked-in `bin/` files are Unix Hermit wrappers and cannot bootstrap
+the toolchain from Git Bash or PowerShell on Windows. Use native PowerShell and
+Windows-native tools for desktop development and packaging.
+
+### 1. Install the command-line toolchain
+
+Open a Shell and install Git, Node.js, Rustup, and Just with WinGet:
+
+```powershell
+winget install --id Git.Git -e
+winget install --id OpenJS.NodeJS.LTS -e
+winget install --id Rustlang.Rustup -e
+winget install --id Casey.Just -e
+```
+
+Node provides `node`, `npm`, and Corepack. Rustup manages the Rust compiler and
+Cargo version selected by this repository. Just runs repository tasks. Restart
+your shell or IDE after these installations so new terminals inherit the
+updated user and system `PATH` values.
+
+Windows CI currently uses Node 24.14.1. The repository pins pnpm 11.4.0 in the
+root `package.json` and Rust 1.95.0 in `rust-toolchain.toml`.
+
+### 2. Enable pnpm through Corepack
+
+Node is normally installed under `C:\Program Files`, so creating Corepack's
+`pnpm` and `pnpx` shims beside Node requires an elevated shell. Open
+**PowerShell as Administrator** and run:
+
+```powershell
+corepack enable pnpm
+```
+
+`corepack enable` installs the launch shims; it does not necessarily download
+pnpm itself. Close the elevated shell, open a normal PowerShell terminal in the
+repository, and run the version checks below. The first `pnpm --version` call
+reads the root `packageManager` field and downloads pnpm 11.4.0 into Corepack's
+per-user cache if it is not already present.
+
+```powershell
+cd DRIVE:\path\to\buzz
+node --version
+pnpm --version
+rustc --version
+cargo --version
+just --version
+```
+
+The first `rustc` or `cargo` invocation in this repository may similarly make
+Rustup download the Rust 1.95.0 MSVC toolchain selected by
+`rust-toolchain.toml`. Allow those first-run downloads to finish before
+continuing.
+
+If a newly opened Shell still cannot find Cargo, first restart the shell or the IDE.
+As a temporary fix for the current shell only, prepend Rustup's normal binary directory:
+
+```powershell
+$env:PATH = "$env:USERPROFILE\.cargo\bin;$env:PATH"
+```
+
+This command does not install Rust. If `cargo.exe` is missing from that
+directory even though WinGet reports Rustup as installed, repair the stale
+installation by reinstalling the official package:
+
+```powershell
+winget install --id Rustlang.Rustup -e --force
+```
+
+### 3. Install the native C++ build tools
+
+Tauri and the Rust Windows target require Microsoft's linker, C/C++ libraries,
+Windows SDK, CMake, and related build tools. Install Visual Studio 2022 Build
+Tools from PowerShell:
+
+```powershell
+winget install --id Microsoft.VisualStudio.2022.BuildTools -e `
+	--override "--wait --passive --add Microsoft.VisualStudio.Workload.VCTools --includeRecommended"
+```
+
+Alternatively, open **Visual Studio Installer**, select **Build Tools 2022**,
+choose **Modify**, and install **Desktop development with C++**, including the
+MSVC v143 build tools, a Windows 11 SDK, and C++ CMake tools for Windows.
+
+Restart Windows after installing or changing the Visual Studio Build Tools.
+Windows 11 normally includes the WebView2 runtime used by Tauri; install the
+Microsoft Edge WebView2 Evergreen Runtime only if Tauri reports that it is
+missing.
+
+### 4. Install dependencies and run checks
+
+Use a normal, non-elevated PowerShell terminal for repository work:
+
+```powershell
+pnpm install --frozen-lockfile
+pnpm -C desktop typecheck
+pnpm -C desktop test
+pnpm -C desktop dev
+```
+
+The final command starts the frontend-only Vite development server.
+Run `pnpm install --frozen-lockfile` again whenever `pnpm-lock.yaml` changes.
+
+## Build Windows installers locally
+
+Build the five release sidecars required by `src-tauri/tauri.windows.conf.json`,
+then copy them to the target-qualified names Tauri expects:
+
+```powershell
+cargo build --release `
+	-p buzz-acp `
+	-p buzz-agent `
+	-p buzz-dev-mcp `
+	-p git-credential-nostr `
+	-p buzz-cli
+
+$target = "x86_64-pc-windows-msvc"
+$destination = "desktop\src-tauri\binaries"
+New-Item -ItemType Directory -Force $destination | Out-Null
+
+"buzz-acp", "buzz-agent", "buzz-dev-mcp", "git-credential-nostr", "buzz" |
+	ForEach-Object {
+		Copy-Item -Force `
+			"target\release\$_.exe" `
+			"$destination\$_-$target.exe"
+	}
+```
+
+The same sidecars support native desktop development. To run the Tauri app in
+development mode after copying them, use:
+
+```powershell
+pnpm -C desktop tauri dev
+```
+
+Close any running `buzz-desktop.exe` before packaging because Windows locks the
+release executable. Then build the application and its MSI and NSIS installers:
+
+```powershell
+pnpm -C desktop tauri build
+```
+
+`pnpm tauri build` runs the frontend build automatically. The Installers
+will be created in `desktop\src-tauri\target\release\bundle\msi` and
+`desktop\src-tauri\target\release\bundle\nsis`.
+
 ## Structure
 
 - `src/shared` - reusable app-wide code (`ui`, `lib`, `styles`)