Rule node docs (#2369)

* Add a note about resource support for "AI request" node doc

* New doc for "mqtt" rule node

* New doc for "acknowledge" rule node

* New doc for "checkpoint" rule node

* Add overview paragraph for flow nodes

* New doc for "rule chain" node

* New doc for "output" node

* Rule Nodes -> Rule nodes

* Add introductory paragraph for analytics nodes

Author: dskarzh

_data/docs-home.yml

@@ -76,7 +76,7 @@ toc:
       path: /docs/user-guide/rule-engine-2-0/re-getting-started/
     - title: Queues
       path: /docs/user-guide/rule-engine-2-5/queues/
-    - title: Rule Nodes
+    - title: Rule nodes
       path: /docs/user-guide/rule-engine-2-0/nodes/
     - title: Data processing & actions
       section:
@@ -118,7 +118,7 @@ toc:
           path: /docs/user-guide/rule-engine-2-5/tutorials/queues-for-synchronization/
         - title: Using queues for message reprocessing
           path: /docs/user-guide/rule-engine-2-5/tutorials/queues-for-message-reprocessing/
-    - title: Custom Rule Nodes
+    - title: Custom rule nodes
       path: /docs/user-guide/contribution/rule-node-development/
     - title: Templatization
       path: /docs/user-guide/templatization/

_data/paas-eu/docs-home.yml

@@ -115,7 +115,7 @@ toc:
       path: /docs/paas/eu/user-guide/rule-engine-2-0/overview/
     - title: Getting started with Rule Engine
       path: /docs/paas/eu/user-guide/rule-engine-2-0/re-getting-started/
-    - title: Rule Nodes
+    - title: Rule nodes
       path: /docs/paas/eu/user-guide/rule-engine-2-0/nodes/
     - title: Data processing & actions
       section:

_data/paas/docs-home.yml

@@ -115,7 +115,7 @@ toc:
       path: /docs/paas/user-guide/rule-engine-2-0/overview/
     - title: Getting Started
       path: /docs/paas/user-guide/rule-engine-2-0/re-getting-started/
-    - title: Rule Nodes
+    - title: Rule nodes
       path: /docs/paas/user-guide/rule-engine-2-0/nodes/
     - title: Data processing & actions
       section:

_data/pe/docs-home.yml

@@ -107,7 +107,7 @@ toc:
     path: /docs/pe/user-guide/rule-engine-2-0/re-getting-started/
   - title: Queues
     path: /docs/pe/user-guide/rule-engine-2-5/queues/
-  - title: Rule Nodes
+  - title: Rule nodes
     path: /docs/pe/user-guide/rule-engine-2-0/nodes/
   - title: Data processing & actions
     section:
@@ -149,7 +149,7 @@ toc:
         path: /docs/user-guide/rule-engine-2-5/tutorials/queues-for-synchronization/
       - title: Using queues for message reprocessing
         path: /docs/user-guide/rule-engine-2-5/tutorials/queues-for-message-reprocessing/
-  - title: Custom Rule Nodes
+  - title: Custom rule nodes
     path: /docs/user-guide/contribution/rule-node-development/
   - title: Templatization
     path: /docs/pe/user-guide/templatization/

_includes/docs/user-guide/rule-engine-2-0/nodes/analytics/index.md

@@ -1,3 +1,7 @@
+Analytics nodes perform statistical calculations and aggregations on incoming data streams and data across entities.
+
+These nodes can compute statistical metrics (minimum, maximum, sum, average, count) from streaming data, track alarm counts or periodically aggregate attributes and telemetry data of entities.
+
 - <span class="item-pe product-label-padding">[aggregate latest](/docs/user-guide/rule-engine-2-0/nodes/analytics/aggregate-latest)</span> — Periodically does aggregation of child entities attributes or latest timeseries for specified set of parent entities.
 - <span class="item-pe product-label-padding">[aggregate stream](/docs/user-guide/rule-engine-2-0/nodes/analytics/aggregate-stream)</span> — Calculates MIN/MAX/SUM/AVG/COUNT/UNIQUE based on the incoming data stream.
 - <span class="item-pe product-label-padding">[alarms count](/docs/user-guide/rule-engine-2-0/nodes/analytics/alarms-count)</span> — Count alarms when receives input message about new alarm.

_includes/docs/user-guide/rule-engine-2-0/nodes/external/ai-request.md

@@ -64,8 +64,7 @@ Attach files to provide additional context to the AI model. Resources are sent a
 
 #### Adding resources
 
-Click the **AI resources** field and select one or more files from your resource library, or click **Create new** to upload new files. Resources must be of type **General** and are
-validated when the node is initialized.
+Click the **AI resources** field and select one or more files from your resource library, or click **Create new** to upload new files. Resources must be of type **General**.
 
 #### Supported resource types
 
@@ -82,6 +81,12 @@ To include attached resources in the AI request, the node must convert them to o
 {% endcapture %}
 {% include templates/info-banner.md content=resource_fallback_note %}
 
+{% capture resource_support_note %}
+**Note**: The actual resource types supported (files, images, PDFs, etc.) depend on the specific AI model integration being used. 
+While the node can convert resources to the content types listed above, not all model providers support all content types.
+{% endcapture %}
+{% include templates/info-banner.md content=resource_support_note %}
+
 ### Response format
 
 Specifies the structure of the AI model's output.
@@ -268,7 +273,7 @@ Consider the typical response time of your chosen model when configuring this va
       format.
 3. The chat request is sent to the configured AI model with the specified timeout.
 4. When the AI responds:
-    - The response text is validated to ensure it is a valid JSON object (if not, it is wrapped in a JSON object with a "response" key).
+    - The response text is validated to ensure it is a valid JSON object (if not, it is wrapped in a JSON object with a `response` key).
     - The response replaces the incoming message data (or is sent as a new message if force acknowledgement is enabled).
     - The originator, message type, and metadata from the incoming message remain unchanged.
 5. The resulting message is forwarded via the `Success` connection.

_includes/docs/user-guide/rule-engine-2-0/nodes/external/index.md

@@ -12,7 +12,7 @@ This allows rule chains to integrate with external infrastructure and services a
 - [azure iot hub](/docs/user-guide/rule-engine-2-0/nodes/external/azure-iot-hub) — Node will send full Message payload to the Azure IoT Hub device.
 - [gcp pubsub](/docs/user-guide/rule-engine-2-0/nodes/external/gcp-pubsub) — publishes incoming message data to [Google Cloud Pub/Sub](https://cloud.google.com/pubsub){:target="_blank"} topic and return response metadata in the outgoing message.
 - [kafka](/docs/user-guide/rule-engine-2-0/nodes/external/kafka) — publishes messages to [Apache Kafka](https://kafka.apache.org/){:target="_blank"} topic, sending the incoming message data as the record value.
-- [mqtt](/docs/user-guide/rule-engine-2-0/nodes/external/mqtt) — Publish incoming message payload to the topic of the configured MQTT broker with QoS AT_LEAST_ONCE.
+- [mqtt](/docs/user-guide/rule-engine-2-0/nodes/external/mqtt) — publishes incoming message data to an external MQTT broker using QoS 1 (at least once), with support for dynamic topic patterns, multiple authentication methods, and TLS/SSL encryption.
 - [rabbitmq](/docs/user-guide/rule-engine-2-0/nodes/external/rabbitmq) — publishes messages to [RabbitMQ](https://www.rabbitmq.com/){:target="_blank"} exchanges, sending the incoming message data as the message body.
 - [rest api call](/docs/user-guide/rule-engine-2-0/nodes/external/rest-api-call) — Invoke REST API calls to the external REST server.
 - [send email](/docs/user-guide/rule-engine-2-0/nodes/external/send-email) — Node sends incoming message using configured Mail Server.