feat(M6): Weitere Hosts — MiniApps in Fenstern + AI-Agenten-Ausgabe-Bloecke (#364)

- Windows-Host: openMiniAppWindow-Helper + MiniAppWindowContent (windowStore);
  Oeffnen-Buttons im Chat-Block (MiniAppBlock) und Dashboard-Widget
- AI-Agenten-Host: Core-Tool send_miniapp (app/ai/miniapp_tools.py) —
  miniapp-Block in Agent-Chat (approval_request-Praezedenz), Permission
  fail-closed gegen aufrufenden User pro App; Registrierung im lifespan
- agent_loop: tool_context + agent_name (Raum-Aufloesung)
- Fix: MiniAppBlock nutzt useMiniapps (component-Feld) statt Legacy /comm/miniapps
- Tests: M6 7/7 (TDD rot->gruen), Backend-Regression 57/57, Vitest 26/26
  (4 neue Window-Tests), tsc clean, build OK

app/ai/agent_loop.py

@@ -197,6 +197,7 @@ async def run_react_loop(
         "tenant_id": str(tenant_id),
         "user_id": str(user_id),
         "db": db,
+        "agent_name": getattr(agent_definition, "name", "Agent"),
     }
 
     # Audit helper — records every tool call in the audit log.

app/ai/miniapp_tools.py

@@ -0,0 +1,127 @@
+"""Core AI agent tools for MiniApp output (Phase M6).
+
+``send_miniapp`` lets an agent embed a MiniApp as an interactive output
+block in its chat room (block_type "miniapp", approval_request precedent
+from agent_loop). Permission is checked fail-closed against the CALLING
+user for the target app's own permission — the tool never widens access.
+"""
+
+from __future__ import annotations
+
+import logging
+import uuid
+from typing import Any
+
+from app.ai.tool_registry import get_tool_registry
+from app.core.permissions import check_permission, resolve_permissions
+from app.plugins.miniapp_registry import get_miniapp_registry
+
+logger = logging.getLogger(__name__)
+
+
+def _get_komm_contract() -> Any | None:
+    """Resolve the kommunikation contract (None when plugin inactive)."""
+    from app.plugins.builtins.contracts import get_contract_registry
+
+    return get_contract_registry().get("kommunikation")
+
+
+async def _send_miniapp_handler(arguments: dict[str, Any], context: dict[str, Any]) -> str:
+    """Send a MiniApp as an output block to the agent's chat room."""
+    app_id = str(arguments.get("app_id") or "")
+    settings = arguments.get("settings") or {}
+    if not isinstance(settings, dict):
+        settings = {}
+
+    app = get_miniapp_registry().get_app(app_id)
+    if app is None:
+        return f"Error: MiniApp '{app_id}' not found"
+
+    db = context.get("db")
+    tenant_id = context.get("tenant_id")
+    user_id = context.get("user_id")
+    if not tenant_id or not user_id or db is None:
+        return "Error: Missing tenant/user context"
+
+    try:
+        tenant_uuid = uuid.UUID(str(tenant_id))
+        user_uuid = uuid.UUID(str(user_id))
+    except (ValueError, TypeError):
+        return "Error: Invalid tenant/user context"
+
+    # Fail-closed permission check against the calling user
+    resolved = await resolve_permissions(db, user_uuid, tenant_uuid)
+    if app.permission and not check_permission(resolved, app.permission):
+        return f"Error: Permission '{app.permission}' required for MiniApp '{app.app_id}'"
+
+    komm = _get_komm_contract()
+    if komm is None:
+        return "Error: Communication plugin not available"
+
+    agent_name = str(context.get("agent_name") or "Agent")
+    conv_id = await komm.find_locked_room_id(
+        db=db,
+        tenant_id=tenant_uuid,
+        plugin_name="automation",
+        title=f"Agent: {agent_name}",
+    )
+    if conv_id is None:
+        return f"Info: No agent chat room found for '{agent_name}' — MiniApp not posted"
+
+    agent_id_raw = context.get("agent_id")
+    try:
+        sender_id = uuid.UUID(str(agent_id_raw)) if agent_id_raw else None
+    except (ValueError, TypeError):
+        sender_id = None
+
+    await komm.send_message(
+        db=db,
+        tenant_id=tenant_uuid,
+        conversation_id=conv_id,
+        sender_id=sender_id,
+        sender_type="agent",
+        content=f"MiniApp: {app.name}",
+        content_format="text",
+        blocks=[
+            {
+                "block_type": "miniapp",
+                "block_data": {"app_id": app_id, "config": settings},
+                "sort_order": 0,
+            }
+        ],
+    )
+    return f"MiniApp '{app_id}' sent to chat"
+
+
+# ─── Registration ───
+
+
+def register_miniapp_tools() -> None:
+    """Register the MiniApp agent tools in the global tool registry."""
+    registry = get_tool_registry()
+    registry.register(
+        name="send_miniapp",
+        description=(
+            "Eine MiniApp als interaktiven Ausgabe-Block in den Agent-Chat senden "
+            "(z.B. ein Widget mit Einstellungen anzeigen). Verfügbare App-IDs "
+            "stehen in /api/v1/miniapps."
+        ),
+        parameters={
+            "type": "object",
+            "properties": {
+                "app_id": {
+                    "type": "string",
+                    "description": "ID der MiniApp (z.B. recent_contacts, tasks_summary)",
+                },
+                "settings": {
+                    "type": "object",
+                    "description": "Optionale Einstellungen für die MiniApp-Instanz",
+                },
+            },
+            "required": ["app_id"],
+        },
+        handler=_send_miniapp_handler,
+        plugin_name="system",
+        required_permission=None,  # per-app check inside the handler (fail-closed)
+        category="ui",
+    )