Windows support: psmux hint, install.ps1, updated docs

PLAN.md

@@ -66,13 +66,14 @@ is still open. For the full requirements, see [SPEC.md](SPEC.md).
 - [ ] Paginate/scroll the secrets diff table for secrets with many fields
       instead of relying on terminal wrapping.
 
-## Phase 3 — Windows-native support (open, secondary priority)
+## Phase 3 — Windows-native support (done)
 
-- [ ] Detect OS at runtime; on native Windows (no WSL), fall back to
-      `wt.exe split-pane` instead of `tmux` for the status panes.
-- [ ] Document/implement that `Esc`-triggered session close is **not**
-      available in the native Windows fallback — the panes must be closed
-      manually there.
+- [x] Windows support via [psmux](https://github.com/marlocarlo/psmux) —
+      a native, tmux-compatible terminal multiplexer. kctl-tui works
+      without code changes; `CheckTool("tmux")` error message includes
+      Windows-specific install hint.
+- [x] `install.ps1` — PowerShell install script for Windows.
+- [x] Updated README and SPEC with Windows + psmux setup instructions.
 
 ## Phase 4 — Nice-to-haves (open, not committed)
 

README.md

@@ -68,12 +68,16 @@ See [SPEC.md](SPEC.md) for the full requirements and design rationale, and
   Configuration below - they must already exist in your kubeconfig, e.g.
   added via `aws eks update-kubeconfig`).
 - `k9s` (used for the two status panes).
-- `tmux` (used for the 3-pane layout). On Windows, this means running
-  kctl-tui inside **WSL** — `tmux` has no native Windows port. Native
-  Windows Terminal has its own split-pane feature, but it cannot be
-  scripted from inside a pane the way `tmux` can, so the automated 3-pane
-  layout and the `Esc` session handling described above are only fully
-  supported under Linux/WSL. See SPEC.md section 3.6 for details.
+- `tmux` (used for the 3-pane layout). On **Linux/macOS**, install
+  `tmux` via your package manager. On **Windows**, install
+  [psmux](https://github.com/marlocarlo/psmux) — a native,
+  tmux-compatible terminal multiplexer:
+  ```powershell
+  scoop install psmux
+  # or
+  cargo install psmux
+  ```
+  psmux provides a `tmux` command, so kctl-tui works without changes.
 - `aws` CLI, configured with credentials, only needed for the secrets
   workflow.
 
@@ -85,6 +89,15 @@ See [SPEC.md](SPEC.md) for the full requirements and design rationale, and
 curl -fsSL https://raw.githubusercontent.com/skoelle/kctl-tui/main/install.sh | bash
 ```
 
+### Quick install (Windows)
+
+```powershell
+irm https://raw.githubusercontent.com/skoelle/kctl-tui/main/install.ps1 | iex
+```
+
+This downloads the latest release binary for your architecture from
+GitHub Releases and installs it to your PATH.
+
 This downloads the latest release binary for your OS/architecture from
 GitHub Releases and installs it to `/usr/local/bin/kctl-tui`.
 
@@ -167,11 +180,19 @@ aws_sso_login_command: "aws sso login"
 that way — it typically contains your organization's internal account ID,
 context naming, and label names.
 
-## WSL setup notes
+## Windows notes
 
-If `kubectx`/`kubens` or `kctl-tui` report a missing kubeconfig inside WSL,
-your kubeconfig most likely only exists on the Windows side. Symlink it
-into WSL:
+On native Windows (without WSL), install [psmux](https://github.com/marlocarlo/psmux)
+for the 3-pane layout. psmux is a native Windows terminal multiplexer
+that is tmux-compatible — kctl-tui works without code changes:
+
+```powershell
+scoop install psmux
+# or
+cargo install psmux
+```
+
+If you prefer WSL, symlink your kubeconfig into WSL:
 
 ```bash
 mkdir -p ~/.kube

SPEC.md

@@ -167,18 +167,15 @@ The `context_template` replaces `{region}`, `{account_id}`, `{env}`, and
 selected environment/context. The resolved value must match an existing
 context in your kubeconfig (e.g. added via `aws eks update-kubeconfig`).
 
-**Platform limitation on Windows without WSL:** `kill-session` is
-tmux-specific. Windows Terminal (`wt.exe`) offers no equivalent scripting
-to end the session from inside a pane. On plain Windows (without WSL),
-only a simplified flow is possible: k9s panes are closed manually (`q`,
-then `Ctrl+Shift+W`); automatic session termination is unavailable there.
-This limitation is the main reason the primary target system is set to
-Linux/WSL.
+**Windows support:** On native Windows, install
+[psmux](https://github.com/marlocarlo/psmux) — a native, tmux-compatible
+terminal multiplexer. psmux provides a `tmux` command, so kctl-tui works
+without code changes (including `Esc`-triggered session termination).
+Alternatively, run kctl-tui inside WSL with standard `tmux`.
 
 ## 4. Non-functional requirements
 
-- **Primary platform Linux/WSL**, secondary native Windows with reduced
-  functionality.
+- **Primary platform Linux/WSL**, secondary native Windows (via psmux).
 - **Single-binary distribution** without external runtime dependency (Go
   provides this natively).
 - **External dependencies**: `kubectl` mandatory; `tmux`, `k9s`, `aws-cli`

install.ps1

@@ -0,0 +1,74 @@
+# Install script for kctl-tui on Windows.
+# Downloads the latest GitHub release binary matching the current architecture
+# and installs it to your PATH.
+#
+# Usage (PowerShell):
+#   irm https://raw.githubusercontent.com/skoelle/kctl-tui/main/install.ps1 | iex
+#
+# Or save and run locally:
+#   .\install.ps1
+#
+# Requires: PowerShell 5.1+, internet access.
+
+$ErrorActionPreference = "Stop"
+
+$Repo = "skoelle/kctl-tui"
+$BinName = "kctl-tui"
+
+# --- Detect architecture ---
+$arch = $env:PROCESSOR_ARCHITECTURE
+switch ($arch) {
+    "AMD64"   { $goarch = "amd64" }
+    "ARM64"   { $goarch = "arm64" }
+    default {
+        Write-Error "Unsupported architecture: $arch"
+        exit 1
+    }
+}
+
+# --- Determine install directory ---
+$installDir = "$env:USERPROFILE\bin"
+if (-not (Test-Path $installDir)) {
+    New-Item -ItemType Directory -Path $installDir | Out-Null
+}
+
+# Add to PATH if not already there
+$currentPath = [Environment]::GetEnvironmentVariable("Path", "User")
+if ($currentPath -notlike "*$installDir*") {
+    [Environment]::SetEnvironmentVariable("Path", "$currentPath;$installDir", "User")
+    $env:Path = "$env:Path;$installDir"
+    Write-Host "Added $installDir to your PATH."
+}
+
+# --- Query GitHub API for latest release ---
+Write-Host "Detecting latest release for $Repo ..."
+try {
+    $release = Invoke-RestMethod -Uri "https://api.github.com/repos/$Repo/releases/latest" -UseBasicParsing
+} catch {
+    Write-Error "Failed to reach the GitHub API (network error). Check your internet connection and try again."
+    exit 1
+}
+
+$tag = $release.tag_name
+if (-not $tag) {
+    Write-Error "Could not find a published release for $Repo. No release has been tagged yet."
+    exit 1
+}
+
+Write-Host "Latest release: $tag"
+
+# --- Download binary ---
+$asset = "kctl-tui-windows-${goarch}.exe"
+$url = "https://github.com/$Repo/releases/download/$tag/$asset"
+$outFile = "$installDir\$BinName.exe"
+
+Write-Host "Downloading $asset ($tag) ..."
+try {
+    Invoke-WebRequest -Uri $url -OutFile $outFile -UseBasicParsing
+} catch {
+    Write-Error "Download failed: $_"
+    exit 1
+}
+
+Write-Host "Installed $BinName to $outFile"
+Write-Host "Done. Run '$BinName' to get started."

internal/kubeexec/kubeexec.go

@@ -182,8 +182,11 @@ func RunAWSLogin(loginCommand string) *exec.Cmd {
 // Returns nil if found, or a descriptive error if not.
 func CheckTool(name string) error {
 	_, err := exec.LookPath(name)
-	if err != nil {
-		return fmt.Errorf("%q not found in PATH — please install it first", name)
-	}
+	if err == nil {
 		return nil
 	}
+	if name == "tmux" {
+		return fmt.Errorf("%q not found in PATH — install tmux (Linux/macOS) or psmux (Windows: scoop install psmux or cargo install psmux)", name)
+	}
+	return fmt.Errorf("%q not found in PATH — please install it first", name)
+}