Fix pr-review workflow permissions: grant issues:write for failure tracking

[Copilot]

Problem

Workflow validation failed for trigger-pr-review.yml:

Error calling workflow 'elastic/ai-github-actions/.github/workflows/gh-aw-pr-review.lock.yml@aadcfd18c43d3f03138e53a725b3b176ce1448ba'. 
The nested job 'conclusion' is requesting 'issues: write', but is only allowed 'issues: read'.
The nested job 'safe_outputs' is requesting 'issues: write', but is only allowed 'issues: read'.

Root Cause

The compiled lock file (v0.87.4) includes conclusion and safe_outputs jobs that require issues: write to create failure tracking issues (via the report-failure-as-issue feature enabled by default). The trigger file only granted issues: read.

Changes

• gh-agent-workflows/pr-review/example.yml: Changed issues: read → issues: write with updated comment
• .github/workflows/trigger-pr-review.yml: Regenerated from example.yml via make compile

The fix aligns caller permissions with the lock file's internal job requirements.