feat(data): store ssh workspaces on app_settings

src/ClaudeDo.Data/Models/SshWorkspace.cs

@@ -0,0 +1,29 @@
+using System.Text.RegularExpressions;
+
+namespace ClaudeDo.Data.Models;
+
+/// <summary>A server an interactive claude session can be started on via ssh; connection details live in the user's ssh config.</summary>
+public sealed record SshWorkspace(string Id, string Name, string Host, string RemotePath)
+{
+    // A leading '-' would make ssh parse the alias as an option (-oProxyCommand=... runs local code).
+    private static readonly Regex HostPattern = new(@"^[A-Za-z0-9._@][A-Za-z0-9._@-]*$", RegexOptions.Compiled);
+
+    /// <summary>Returns the first invalid field ("name", "host", "path") or null when valid.</summary>
+    public static string? Validate(SshWorkspace w)
+    {
+        if (string.IsNullOrWhiteSpace(w.Name)) return "name";
+        if (string.IsNullOrEmpty(w.Host) || !HostPattern.IsMatch(w.Host)) return "host";
+        var p = w.RemotePath ?? "";
+        if (!(p.StartsWith('/') || p.StartsWith('~')) || p.Contains('\'') || p.Contains('\n') || p.Contains('\r'))
+            return "path";
+        return null;
+    }
+
+    /// <summary>Single-quotes a validated remote path for a POSIX shell, leaving a leading <c>~</c> unquoted so it still expands.</summary>
+    public static string QuoteRemotePath(string path)
+    {
+        if (path == "~") return "~";
+        if (path.StartsWith("~/")) return "~/'" + path[2..] + "'";
+        return "'" + path + "'";
+    }
+}