feat: Chatbot-Workflows mit Ollama-Memory und Session-Management

- docker-compose: extra_hosts für host.docker.internal (Ollama-Zugang)
- ollama-chatbot: Gesprächsverlauf per session_id in PostgreSQL
- ollama-chat-cleanup: stündliche TTL-Bereinigung (2h Inaktivität)
- ollama-chat-delete: DELETE /webhook/chat-session Endpoint

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

imports/workflows/ollama-chat-delete.json

@@ -0,0 +1,59 @@
+{
+  "id": "1003",
+  "name": "Chatbot Session löschen",
+  "nodes": [
+    {
+      "parameters": {
+        "httpMethod": "DELETE",
+        "path": "chat-session",
+        "responseMode": "responseNode",
+        "options": {}
+      },
+      "id": "node-wh-002",
+      "name": "Webhook",
+      "type": "n8n-nodes-base.webhook",
+      "typeVersion": 2,
+      "position": [100, 300],
+      "webhookId": "ollama-chat-delete"
+    },
+    {
+      "parameters": {
+        "operation": "executeQuery",
+        "query": "DELETE FROM chat_sessions WHERE session_id = $1 RETURNING session_id",
+        "additionalFields": {
+          "queryParams": "={{ JSON.stringify([$json.body.session_id]) }}"
+        }
+      },
+      "id": "node-pg-004",
+      "name": "Delete Session",
+      "type": "n8n-nodes-base.postgres",
+      "typeVersion": 2.5,
+      "position": [300, 300],
+      "credentials": {
+        "postgres": {
+          "id": "SETUP_REQUIRED",
+          "name": "n8n PostgreSQL"
+        }
+      }
+    },
+    {
+      "parameters": {
+        "respondWith": "json",
+        "responseBody": "={{ JSON.stringify({ deleted: $input.first().json.session_id != null, session_id: $('Webhook').first().json.body.session_id }) }}",
+        "options": {}
+      },
+      "id": "node-rw-002",
+      "name": "Respond",
+      "type": "n8n-nodes-base.respondToWebhook",
+      "typeVersion": 1.1,
+      "position": [500, 300]
+    }
+  ],
+  "connections": {
+    "Webhook":        { "main": [[{ "node": "Delete Session", "type": "main", "index": 0 }]] },
+    "Delete Session": { "main": [[{ "node": "Respond",        "type": "main", "index": 0 }]] }
+  },
+  "active": false,
+  "settings": { "executionOrder": "v1" },
+  "tags": []
+}