Docs: Add documentation for auto-triage github action (#97672)

* Add documentation about auto-triager bot

* Add diagram

* Update links to prompts and labels files

.github/bot.md

@@ -28,3 +28,83 @@ try to cherry-pick the PR merge commit into that branch and open a PR. You must
 If there are merge conflicts the bot will write a comment on the source PR saying the cherry-pick failed. In this case you have to do the cherry pick and backport PR manually. 
 
 The backport logic is written [here](https://github.com/grafana/grafana-github-actions/blob/main/backport/backport.ts)
+
+## Auto triager bot
+
+The auto triager bot is a github action that **assigns** labels to issues based on the issue contents. The logic to assign
+labels is its own program and lives [here](https://github.com/grafana/auto-triager). It uses an LLM to do this.
+
+The bot runs **every time** a new issue is opened in the grafana/grafana repository. You can find the bot definition [here](https://github.com/grafana/grafana/blob/main/.github/workflows/issue-opened.yml#L61)
+
+The job only assign labels when the issue author is not a member of the Grafana organization in **GitHub**. The bot concurrency is 1.
+
+This bot is not responsible for assigning teams, the [commands](https://github.com/grafana/grafana/blob/main/.github/workflows/commands.yml) workflow is responsible for doing that
+
+### General diagram
+
+```mermaid
+sequenceDiagram
+    actor User
+    participant GH as GitHub
+    participant AT as Auto Triager Job
+    participant ATP as Auto Triager Program
+    participant LLM as LLM Service
+    participant CJ as Commands Job
+
+    User->>GH: Opens Issue
+    GH->>GH: Check if user in Grafana org
+    alt User not in Grafana org
+        GH->>AT: Trigger Auto Triager Job
+        AT->>ATP: Execute program
+        ATP->>LLM: Send issue content & categories
+        LLM-->>ATP: Return matching categories
+        ATP-->>GH: Assign labels to issue
+        GH->>CJ: Trigger Commands Job
+        CJ->>CJ: Read commands.json
+        CJ-->>GH: Assign teams based on labels
+    end
+```
+
+### Team definitions
+
+The team associated with labels are defined [here](https://github.com/grafana/grafana/blob/main/.github/commands.json). 
+This bot is not responsible for assigning teams, the [commands](https://github.com/grafana/grafana/blob/main/.github/workflows/commands.yml) workflow is responsible for doing that.
+
+The commands workflow code can be found [here](https://github.com/grafana/grafana-github-actions/tree/main/commands)
+
+### Categories/Labels definitions
+
+The categories (or labels) and the types used to categorize issues are defined in this same repository [here](https://github.com/grafana/grafana/tree/main/.github/workflows/auto-triager) the [prompt](https://github.com/grafana/grafana/blob/main/.github/workflows/auto-triager/prompt.txt) that is passed to the LLM is also defined there.
+
+If you are adding a new category in the auto-triager repository you must define a team that owns the label in the
+[commands.json](https://github.com/grafana/grafana/blob/main/.github/commands.json).
+
+If you remove a label from the [commands.json](https://github.com/grafana/grafana/blob/main/.github/commands.json) and it doesn't have any other 
+team associated with it you must remove it from the [labels file](https://github.com/grafana/grafana/blob/main/.github/workflows/auto-triager/labels.txt)
+
+### Secrets
+
+The bot secrets live in the vault. It uses a [shared workflow](https://github.com/grafana/shared-workflows/tree/main/actions/get-vault-secrets) to get the vault secrets, the
+workflow requires a token with `contents:read` and `id-token:write` scopes for it to work.
+
+### How to detect the bot is working?
+
+The list of [unlabeled issues](https://github.com/grafana/grafana/issues?q=is%3Aopen+is%3Aissue+no%3Alabel) should remain empty as long as the bot is running.
+There might be issues in the list if some team member removed all labels, but if the list grows to more
+than 5 it is likely the bot is not working correctly.
+
+### What to do if this bot is not working?
+
+You can contact the plugins platform team in slack `#grafana-plugins-platform` and inform about the issue.
+
+### Troubleshooting
+
+Possible reasons why the bot is not working:
+
+* The OpenAI API key is not valid anymore. The action output will show this in its error log. A new key needs to be
+generated via the OpenAI UI and its value updated in vault. See [the action](https://github.com/grafana/grafana/blob/main/.github/workflows/issue-opened.yml#L72) to find the correct path to
+update the key.
+* The Slack webhook URL is not valid anymore. The action output will show this in its error log or the
+#triage-automation-ci channel will stop showing messages about issue triaging. A new slack webhook url needs to be
+generated for the auto triager app and its value updated in vault. 
+* This bot is not responsible for assigning teams, the [commands](https://github.com/grafana/grafana/blob/main/.github/workflows/commands.yml) workflow is responsible for doing that