feat: MCP-Server für remote_execute + Inline-Choice-UI

- Python MCP-Server (stdio, JSON-RPC 2.0) für remote_execute via Claude CLI
- Interner API-Endpoint /api/internal/remote-execute mit Token-Auth
- MCP-Config wird automatisch generiert wenn Remote-Verbindung vorhanden
- Auth-Middleware: /api/internal/ von Auth ausgenommen
- Frontend: :::ASK_USER_CHOICE::: Blöcke als interaktive Buttons rendern
- Streaming: Unvollständige Choice-Blöcke werden während des Streams versteckt
- tool-ui.js: MCP-Tool-Namen generisch normalisieren (mcp__server__tool → tool)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Endpoints/ChatEndpoint.cs

@@ -245,7 +245,7 @@ public static class ChatEndpoint
                 {
                     if (anthropic.IsCliAvailable)
                     {
-                        await anthropic.StreamChatViaCli(res, ctx.ModelId, ctx.SystemPrompt, messages, ctx.ChainId, workspace: ctx.Workspace, allowUserChoice: ctx.Agent?.AllowUserChoice ?? true, planMode: body.PlanMode, webSearch: !string.IsNullOrEmpty(ctx.WebSearchVersion), sessionId: sessionId, workCt: workCt, sseCt: sseCt);
+                        await anthropic.StreamChatViaCli(res, ctx.ModelId, ctx.SystemPrompt, messages, ctx.ChainId, workspace: ctx.Workspace, allowUserChoice: ctx.Agent?.AllowUserChoice ?? true, planMode: body.PlanMode, webSearch: !string.IsNullOrEmpty(ctx.WebSearchVersion), sessionId: sessionId, remoteMgr: remoteMgr, workCt: workCt, sseCt: sseCt);
                     }
                     else
                     {

Endpoints/InternalEndpoint.cs

@@ -0,0 +1,73 @@
+using System.IO;
+using System.Linq;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using Gott.Services;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Routing;
+
+namespace Gott.Endpoints;
+
+/// <summary>
+/// Interne API-Endpoints für MCP-Server und andere lokale Integrationen.
+/// Gesichert über einen internen Token (da Reverse-Proxy den Localhost-Check umgeht).
+/// </summary>
+public static class InternalEndpoint
+{
+    /// <summary>
+    /// Interner Auth-Token – wird beim Start generiert und an MCP-Server übergeben.
+    /// </summary>
+    public static string InternalToken { get; } = System.Guid.NewGuid().ToString("N");
+
+    public static void MapInternalEndpoints(this IEndpointRouteBuilder app)
+    {
+        app.MapPost("/api/internal/remote-execute", HandleRemoteExecute);
+    }
+
+    private static async Task<IResult> HandleRemoteExecute(HttpContext ctx, RemoteConnectionManager mgr)
+    {
+        try
+        {
+            // Token-Check: Header "X-Internal-Token" muss den internen Token enthalten
+            var token = ctx.Request.Headers["X-Internal-Token"].FirstOrDefault() ?? "";
+            if (token != InternalToken)
+                return Results.StatusCode(403);
+
+            using var reader = new StreamReader(ctx.Request.Body);
+            var body = await reader.ReadToEndAsync();
+
+            JsonElement json;
+            try { json = JsonSerializer.Deserialize<JsonElement>(body); }
+            catch { return Results.BadRequest(new { error = "Invalid JSON" }); }
+
+            var command = json.TryGetProperty("command", out var cmd) ? cmd.GetString() ?? "" : "";
+            var sessionId = json.TryGetProperty("sessionId", out var sid) ? sid.GetString() ?? "" : "";
+
+            if (string.IsNullOrEmpty(command))
+                return Results.BadRequest(new { error = "command erforderlich" });
+
+            if (string.IsNullOrEmpty(sessionId))
+                return Results.BadRequest(new { error = "sessionId erforderlich" });
+
+            var conn = mgr.GetBySessionId(sessionId);
+            if (conn == null)
+                return Results.NotFound(new { error = "Keine Remote-Verbindung für diese Session" });
+
+            using var cts = new CancellationTokenSource(System.TimeSpan.FromSeconds(180));
+            var result = await mgr.ExecuteCommand(conn.Id, command, 180, cts.Token);
+
+            return Results.Ok(new
+            {
+                exitCode = result.ExitCode,
+                stdout = result.Output ?? "",
+                stderr = result.Error ?? ""
+            });
+        }
+        catch (System.Exception ex)
+        {
+            return Results.Json(new { error = ex.Message, stackTrace = ex.StackTrace }, statusCode: 500);
+        }
+    }
+}