code-review skill: post inline PR comments instead of single summary comment

Feature request

The code-review:code-review skill currently posts all findings as a single PR comment. This makes it harder to:

• Resolve issues individually — with one comment, you either resolve the whole thing or nothing
• Track which issues are addressed — no per-issue resolve/unresolve state
• Discuss specific issues — replies are threaded under one comment rather than contextual to the code

Requested behavior

Post review findings as inline PR review comments on the specific file and line, similar to how GitHub Copilot reviews work. Use the GitHub API's pull request review endpoint:

POST /repos/{owner}/{repo}/pulls/{number}/reviews
{
  "event": "COMMENT",
  "comments": [
    {"path": "file.py", "line": 42, "body": "Issue description..."},
    {"path": "file.py", "line": 100, "body": "Another issue..."}
  ]
}

This gives each finding its own resolve button and threaded discussion, enabling atomic resolution and tracking.

A summary comment (or the review body) could still provide the overview, but individual issues should be inline.

Current behavior

Step 8 of the skill uses gh pr comment to post a single comment listing all issues. There's no per-issue tracking or resolution.