fix: skip CodeRabbit reviews on bot and release PRs (#9279)

## Problem

CodeRabbit is reviewing release and backport PRs created by bots (e.g.
[#9264](#9264)),
leaving unnecessary review comments.

## Solution

Add ignore rules to `.coderabbit.yaml`:

- **`ignore_usernames`**: `comfy-pr-bot`, `github-actions` — skips
reviews on PRs authored by these bot accounts
- **`ignore_title_keywords`**: `[release]`, `[backport` — skips reviews
on release and backport PRs by title

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9279-fix-skip-CodeRabbit-reviews-on-bot-and-release-PRs-3146d73d3650814c9ebae0d08acbafd6)
by [Unito](https://www.unito.io)

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: christian-byrne

.coderabbit.yaml

@@ -5,3 +5,10 @@ reviews:
   high_level_summary: false
   auto_review:
     drafts: true
+    ignore_title_keywords:
+      - '[release]'
+      - '[backport'
+    ignore_usernames:
+      - comfy-pr-bot
+      - github-actions
+      - github-actions[bot]