Support batching inline comments into a single GitHub Pull Request Review submission

Currently the action posts each inline comment as an independent API call, resulting in multiple separate comment notifications on a PR. GitHub provides a dedicated `Pull Request Reviews API` designed specifically for this use case — it lets a reviewer stage multiple inline comments and submit them together as a single review event with an overall status (`COMMENT`, `APPROVE`, or `REQUEST_CHANGES`).

**Requested behavior:**

Add an input (e.g. `use_pr_review`) that, when enabled, collects all inline comments and submits them together via `POST /repos/{owner}/{repo}/pulls/{pull_number}/reviews` rather than posting each as an individual comment.

**Why this matters:**

- Reduces notification noise — PR authors currently get one notification per comment rather than one for the entire review
- Produces a cohesive review that appears in GitHub's "Reviews" section of the PR timeline, matching the experience of a human reviewer
- Allows an overall review verdict to accompany the inline feedback
- Avoids cluttering the PR comment thread with many independent entries

**Related:**

`use_sticky_comment` addresses a similar concern for top-level comments but doesn't apply to inline code comments, and doesn't use the GitHub review submission model.

Start by locating the action's inline-comment submission path and compare it with the existing use_sticky_comment behavior. Read GitHub's Pull Request Reviews API documentation, then verify that enabling the new input submits all inline comments in one review with an overall status while preserving the current behavior when disabled.

Written by the indexing model from the issue text.