[plan] Expand "Write Operations Fail" troubleshooting entry in common-issues.md

[github-actions]

Objective

Expand the stub "Write Operations Fail" section in docs/src/content/docs/troubleshooting/common-issues.md to provide actionable guidance matching the quality of adjacent sections.

Context

From discussion #21381 (UX Analysis Report — 2026-03-17): The current entry (lines 209–211) is a two-sentence stub, while every adjacent section provides YAML examples, links, and step-by-step resolution. Permission errors are among the most common onboarding blockers.

Current State

### Write Operations Fail

Use safe outputs or request new safe output types.

Proposed Change

Replace the stub with:

### Write Operations Fail

Agentic workflows cannot write to GitHub directly. All writes (issues, comments, PR updates)
must go through the `safe-outputs` system, which validates and executes write operations on
behalf of the workflow.

Ensure your workflow frontmatter declares the safe output types it needs:

```yaml
safe-outputs:
  create-issue:
    title-prefix: "[bot] "
    labels: [automation]
  add-comment:
  update-issue:

If the operation you need is not listed in the Safe Outputs reference,
it may not be supported yet. See the Safe Outputs Specification
for the full list of available output types and their configuration options.

> **Note**: Verify the actual reference links against the existing docs structure before finalizing.

## Files to Modify

- `docs/src/content/docs/troubleshooting/common-issues.md` (single file only)

## Acceptance Criteria

- [ ] Section provides a brief explanation of what safe outputs are
- [ ] Section includes a working YAML example
- [ ] Section includes at least one reference link
- [ ] No other files are modified
- [ ] Content matches the style/format of neighboring sections like "Token Permission Errors"




> Generated by [Plan Command](https://github.com/github/gh-aw/actions/runs/23226577521) for issue #discussion #21381 · [◷](https://github.com/search?q=repo%3Agithub%2Fgh-aw+is%3Aissue+%22gh-aw-workflow-call-id%3A+github%2Fgh-aw%2Fplan%22&type=issues)
> - [x] expires <!-- gh-aw-expires: 2026-03-20T02:46:10.869Z --> on Mar 20, 2026, 2:46 AM UTC

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