feat(ollama): add availability check before model operations

Add `ensureOllamaAvailable` function to lib/ollama.ts for checking and waiting for Ollama server health with configurable timeout.

Integrate the check in GET /api/ollama/models route with 3s timeout to prevent UI blocking, and in POST /api/ollama/pull route with 20s timeout to ensure availability before pulling models.

Update ChatContainer to always render ModelDropdown for better UX when no model is selected.

scripts/ensure-ollama.ps1

@@ -0,0 +1,123 @@
+# Ensures Ollama is running on localhost using WSL (Ubuntu) when available,
+# with a Windows-native fallback. Designed to be idempotent.
+
+param()
+
+$ErrorActionPreference = 'SilentlyContinue'
+
+function Write-Info($msg) { Write-Host "[ensure-ollama] $msg" }
+function Write-Warn($msg) { Write-Warning "[ensure-ollama] $msg" }
+
+function Get-EnvOrDefault([string]$name, [string]$default) {
+    $val = [Environment]::GetEnvironmentVariable($name)
+    if ([string]::IsNullOrWhiteSpace($val)) { return $default }
+    return $val
+}
+
+function Test-Port([int]$Port) {
+    try {
+        $res = Test-NetConnection -ComputerName localhost -Port $Port -WarningAction SilentlyContinue -ErrorAction SilentlyContinue
+        return [bool]$res.TcpTestSucceeded
+    } catch { return $false }
+}
+
+function Wait-Healthy([int]$Port, [int]$TimeoutSeconds) {
+    $deadline = (Get-Date).AddSeconds($TimeoutSeconds)
+    while ((Get-Date) -lt $deadline) {
+        if (Test-Port -Port $Port) { return $true }
+        Start-Sleep -Seconds 1
+    }
+    return $false
+}
+
+function Has-WSL() {
+    return $null -ne (Get-Command wsl.exe -ErrorAction SilentlyContinue)
+}
+
+function WSL-HasDistro([string]$Distro) {
+    try {
+        $list = & wsl.exe -l -q 2>$null
+        return $list -split "`r?`n" | Where-Object { $_ -eq $Distro } | ForEach-Object { $true } | Select-Object -First 1
+    } catch { return $false }
+}
+
+function Invoke-WSL([string]$Distro, [string]$Cmd) {
+    & wsl.exe -d $Distro -- bash -lc $Cmd
+}
+
+function Ensure-Ollama-WSL([string]$Distro) {
+    Write-Info "Verificando/instalando Ollama na WSL ($Distro)"
+    $installCmd = 'command -v ollama >/dev/null 2>&1 || (curl -fsSL https://ollama.com/install.sh | sh)'
+    Invoke-WSL -Distro $Distro -Cmd $installCmd | Out-Null
+}
+
+function Start-Ollama-WSL([string]$Distro) {
+    Write-Info "Iniciando ollama serve em background (WSL:$Distro)"
+    $startCmd = 'mkdir -p "$HOME/.ollama"; nohup ollama serve > "$HOME/.ollama/ollama.log" 2>&1 & disown || true'
+    Invoke-WSL -Distro $Distro -Cmd $startCmd | Out-Null
+}
+
+function Has-Ollama-OnWindows() {
+    return $null -ne (Get-Command ollama -ErrorAction SilentlyContinue)
+}
+
+function Start-Ollama-Windows() {
+    try {
+        $ollama = (Get-Command ollama -ErrorAction Stop).Source
+        Write-Info "Iniciando ollama serve no Windows (hidden)"
+        Start-Process -FilePath $ollama -ArgumentList 'serve' -WindowStyle Hidden | Out-Null
+        return $true
+    } catch {
+        Write-Warn "Ollama não encontrado no PATH do Windows."
+        return $false
+    }
+}
+
+# Main
+$port = [int](Get-EnvOrDefault 'OLLAMA_PORT' '11434')
+$timeout = [int](Get-EnvOrDefault 'OLLAMA_START_TIMEOUT' '20')
+$distro = Get-EnvOrDefault 'OLLAMA_WSL_DISTRO' 'Ubuntu'
+
+if (Test-Port -Port $port) {
+    Write-Info "Porta $port já está respondendo. Nada a fazer."
+    exit 0
+}
+
+if (Has-WSL) {
+    if (-not (WSL-HasDistro -Distro $distro)) {
+        Write-Warn "Distro '$distro' não encontrada. Tentando WSL padrão..."
+        $distro = 'Ubuntu'
+    }
+
+    Write-Info "Tentando iniciar Ollama via WSL ($distro)"
+    Ensure-Ollama-WSL -Distro $distro
+    Start-Ollama-WSL -Distro $distro
+
+    if (Wait-Healthy -Port $port -TimeoutSeconds $timeout) {
+        Write-Info "Ollama disponível em localhost:$port (via WSL)."
+        exit 0
+    } else {
+        Write-Warn "Timeout aguardando Ollama (WSL). Prosseguindo com fallback Windows."
+    }
+}
+
+# Fallback Windows
+if (-not (Has-Ollama-OnWindows)) {
+    Write-Warn "Ollama não encontrado no Windows e WSL não atendeu no tempo."
+    Write-Warn "Instale o Ollama no Windows ou habilite WSL/Ubuntu."
+    exit 0
+}
+
+if (Start-Ollama-Windows) {
+    if (Wait-Healthy -Port $port -TimeoutSeconds $timeout) {
+        Write-Info "Ollama disponível em localhost:$port (Windows)."
+        exit 0
+    } else {
+        Write-Warn "Timeout aguardando Ollama (Windows)."
+        exit 0
+    }
+}
+
+exit 0
+
+