fix(install/windows): repair stale winget registration; refresh PATH after every package manager

When ripgrep/ffmpeg is missing, `winget install <id>` on a package winget
already has registered is treated as an upgrade: it finds no newer version and
exits 0x8A15002B (-1978335189, APPINSTALLER_CLI_ERROR_UPDATE_NOT_APPLICABLE)
without ensuring the binary is actually present. The installer only logged that
code and judged success by `Get-Command rg`, so a stale registration (files
removed outside winget, or a missing alias shim) became a permanent dead-end —
winget kept reporting "already installed" and the user could never reinstall.

Detect that exit code and retry once with `--force` to repair the registration
so the shim reappears.

Also refresh the process PATH after the choco and scoop fallbacks (not just
winget) via a shared helper, so a successful fallback install — or any install
on a box without winget — is no longer misreported as "not installed".

scripts/install.ps1

@@ -892,6 +892,22 @@ function Test-Node {
     return $true
 }
 
+function Update-ProcessPathForPackages {
+    # Rebuild the current process PATH from the persisted User+Machine hives plus
+    # winget's alias-shim directory, so a freshly-installed shim (rg.exe,
+    # ffmpeg.exe) becomes visible to Get-Command in THIS process without
+    # spawning a new shell. Called after every package-manager attempt
+    # (winget/choco/scoop): previously PATH was only refreshed inside the winget
+    # branch, so a successful choco/scoop fallback -- or any install on a box
+    # without winget -- could be misreported as "not installed".
+    $envPath = [Environment]::GetEnvironmentVariable("Path", "User") + ";" + [Environment]::GetEnvironmentVariable("Path", "Machine")
+    $wingetLinks = Join-Path $env:LOCALAPPDATA "Microsoft\WinGet\Links"
+    if (Test-Path $wingetLinks) {
+        $envPath = "$envPath;$wingetLinks"
+    }
+    $env:Path = $envPath
+}
+
 function Install-SystemPackages {
     $script:HasRipgrep = $false
     $script:HasFfmpeg = $false
@@ -961,25 +977,33 @@ function Install-SystemPackages {
             try {
                 $output = winget install --exact --id $pkg --source winget --silent `
                     --accept-package-agreements --accept-source-agreements 2>&1
+                $code = $LASTEXITCODE
                 $output | Out-File -FilePath $log -Encoding utf8
-                "winget exit: $LASTEXITCODE" | Out-File -FilePath $log -Encoding utf8 -Append
+                "winget exit: $code" | Out-File -FilePath $log -Encoding utf8 -Append
+                # 0x8A15002B (-1978335189) = APPINSTALLER_CLI_ERROR_UPDATE_NOT_APPLICABLE.
+                # winget treats `install` on a package it already has registered as
+                # an *upgrade*, finds no newer version, and bails with this code --
+                # even when the binary is gone from disk/PATH (stale registration,
+                # files removed outside winget, or a missing alias shim). We KNOW the
+                # command was missing (that's why we're here), so a plain install
+                # dead-ends forever. Force a reinstall to repair the registration so
+                # the shim reappears.
+                if ($code -eq -1978335189) {
+                    "-> already-installed/no-upgrade; retrying with --force" | Out-File -FilePath $log -Encoding utf8 -Append
+                    $output = winget install --exact --id $pkg --source winget --silent --force `
+                        --accept-package-agreements --accept-source-agreements 2>&1
+                    $output | Out-File -FilePath $log -Encoding utf8 -Append
+                    "winget exit (force): $LASTEXITCODE" | Out-File -FilePath $log -Encoding utf8 -Append
+                }
             } catch {
                 $_ | Out-File -FilePath $log -Encoding utf8 -Append
                 "winget exit: <exception>" | Out-File -FilePath $log -Encoding utf8 -Append
             }
         }
-        # Refresh PATH from both env-var hives AND winget's alias shim directory.
-        # winget exposes packages via "command line aliases" in %LOCALAPPDATA%\
-        # Microsoft\WinGet\Links, which is added to PATH by the AppExecutionAlias
-        # machinery only in *newly-spawned* shells -- not the current process.
-        # Without this addition, Get-Command rg below would falsely return null
-        # immediately after a successful install.
-        $wingetLinks = Join-Path $env:LOCALAPPDATA "Microsoft\WinGet\Links"
-        $envPath = [Environment]::GetEnvironmentVariable("Path", "User") + ";" + [Environment]::GetEnvironmentVariable("Path", "Machine")
-        if (Test-Path $wingetLinks) {
-            $envPath = "$envPath;$wingetLinks"
-        }
-        $env:Path = $envPath
+        # Refresh PATH so packages winget exposed via "command line aliases" in
+        # %LOCALAPPDATA%\Microsoft\WinGet\Links (added to PATH only in
+        # newly-spawned shells, not this process) are visible to Get-Command below.
+        Update-ProcessPathForPackages
         if ($needRipgrep -and (Get-Command rg -ErrorAction SilentlyContinue)) {
             Write-Success "ripgrep installed"
             $script:HasRipgrep = $true
@@ -1005,6 +1029,7 @@ function Install-SystemPackages {
         foreach ($pkg in $chocoPkgs) {
             try { choco install $pkg -y 2>&1 | Out-Null } catch { }
         }
+        Update-ProcessPathForPackages
         if ($needRipgrep -and (Get-Command rg -ErrorAction SilentlyContinue)) {
             Write-Success "ripgrep installed via chocolatey"
             $script:HasRipgrep = $true
@@ -1023,6 +1048,7 @@ function Install-SystemPackages {
         foreach ($pkg in $scoopPkgs) {
             try { scoop install $pkg 2>&1 | Out-Null } catch { }
         }
+        Update-ProcessPathForPackages
         if ($needRipgrep -and (Get-Command rg -ErrorAction SilentlyContinue)) {
             Write-Success "ripgrep installed via scoop"
             $script:HasRipgrep = $true