feat: add Screenshot bot Argus

_apps/screenshot-bot.md

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+---
+title: Screenshot bot Argus
+description: Bot to watch for repository's workflows with tests and pin screenshots differences images to bot's comment of pull request.
+slug: screenshot-report-bot
+screenshots:
+  - https://raw.githubusercontent.com/taiga-family/argus/refs/heads/main/.demo/error-report.png
+  - https://raw.githubusercontent.com/taiga-family/argus/refs/heads/main/.demo/loading.png
+  - https://raw.githubusercontent.com/taiga-family/argus/refs/heads/main/.demo/pr-closed.png
+authors:
+  - nsbarsukov
+repository: taiga-family/argus
+host: https://screenshot-report-bot.vercel.app
+---
+
+**Screenshot bot Argus** is a GitHub App built with [Probot](https://github.com/probot/probot)
+to watch for repository's workflows with tests, download artifacts with screenshots differences images,
+and pin these images to bot's comment of pull request.
+
+> **Why "Argus"?** Argus is a many-eyed "all-seeing" giant in Greek mythology.
+> This character is known for having generated the saying "the eyes of Argus"
+> (being subject to strict scrutiny in one's actions to an invasive, distressing degree).
+> [(c) Wikipedia](https://en.wikipedia.org/wiki/Argus_Panoptes)
+
+Read more about this tool in the article:<br/>
+[«Bots should work, developers should think»: Writing Github App with Node.js](https://medium.com/its-tinkoff/bots-should-work-developers-should-think-writing-github-app-with-node-js-2e8eb049d7e4).
+
+## Setup :rocket:
+
+GitHub Action is recommended approach to use bot.<br />
+However, its deployment as GitHub App is option too.
+
+### As GitHub Action
+
+```yml
+# .github/workflows/screenshot-bot.yml
+on:
+    workflow_run:
+        workflows: [E2E Results] # <-- Choose any workflows to be watched by bot
+        types: [requested, completed]
+        branches-ignore:
+            - 'main'
+            - 'release/**'
+    pull_request:
+        types: [closed]
+
+jobs:
+    awake-screenshot-bot:
+        runs-on: ubuntu-latest
+        permissions:
+            actions: read
+            contents: write
+            pull-requests: write
+        steps:
+            - uses: taiga-family/argus@main
+              env:
+                  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+```
+
+### As GitHub App
+
+You can deploy your own Github App using this code and recipes from [Probot documentation](https://probot.github.io/docs/deployment)
+or use already hosted **[screenshot‑report‑bot](https://github.com/apps/screenshot-report-bot/installations/new)**
+
+## Bot configurations :gear:
+
+Bot has configurable params which can be unique for every GitHub repository.<br>
+Every param is optional, and you can skip this section if default configuration satisfies you.
+
+To pass custom params for bot you should create `screenshot-bot.config.yml` file inside the `.github` directory of repository.
+
+**Example of `screenshot-bot.config.yml` file content** (you can paste it as it is) and **default values** of each param:
+
+```yaml
+# array of RegExp strings to match images inside artifacts (by their path or file name)
+# which shows difference between two screenshot and which will be added to bot report comment
+diff-paths: [
+        # it is default Cypress folder name into which snapshot diffs are put
+        '.*__diff_output__.*',
+    ]
+
+# array of attributes (key="value") for html-tag <img /> (screenshots)
+# e.g. ['width="200px"', 'height="300px"']
+img-attrs: []
+
+# Text which is placed at the beginning of section "Failed tests"
+failed-report-description: ''
+
+# Regular expression string to match images inside artifacts (by their path or file name)
+# which are created by new screenshot tests.
+new-screenshot-mark: '.*==new==.*'
+
+##################################
+# Not relevant for GitHub Action #
+##################################
+
+# array of regular expression strings to match workflow names
+# which should be watched by bot
+workflows: [
+        # all workflows with sub-string "screenshot" in their names
+        '.*screenshot.*',
+    ]
+
+# array of RegExp strings to match branch names which should be skipped by bot
+branches-ignore: []
+```
+
+## What bot can do? :bulb:
+
+-   Holds first PR comment.
+    All workflow updates edit already existing bot comment.
+    No endless stream of comments from bot!
+-   Sets loading state comment when PR is opened or new commits are pushed to PR.
+    ![loading-demo](https://raw.githubusercontent.com/taiga-family/argus/refs/heads/main/.demo/loading.png)
+-   Downloads artifacts from workflow with tests, finds screenshots diffs images, and pins them to the tests failure report.
+    ![error-report-demo](https://raw.githubusercontent.com/taiga-family/argus/refs/heads/main/.demo/error-report.png)
+-   Removes all uploaded images (for current PR) after closing pull request.
+    ![closed-pr-demo](https://raw.githubusercontent.com/taiga-family/argus/refs/heads/main/.demo/pr-closed.png)
+
+## About Permissions :closed_lock_with_key:
+
+If you use bot as GitHub Action it is required to provide `permissions` property in your `yml` file.<br>
+If you use bot as GitHub App it asks for some permissions at the beginning of the bot's installation.<br>
+All requested permissions are really needed, and we do not ask for more permissions than necessary.
+
+#### Permissions
+
+Bot requires the following repository's **permissions**:
+
+-   `actions: read` - to get list of workflow run artifacts and download these artifacts.
+-   `contents: write` - to create new branch for storage of screenshot diffs images
+    and to ability to upload/delete these screenshot diffs images.
+-   `metadata: read` - mandatory for Github App.
+-   `pull_requests: write` - to create/edit PR's comment with bot's tests reports.
+
+#### Events
+
+Bot listens to the following repository's **events**:
+
+-   `pull_request` — bot listens to pull request closing to delete all saved screenshots for current closed PR.
+-   `workflow_run` — bot listens to workflow completion to download artifacts and send tests report as PR comment.