Reuse existing extension workflows in isolated software-factory runs

Desired Behavior

Use the existing extensions issue-to-PR, GitHub PR reviewer, and QA Changes behavior in the Docker software factory. Replace the initial duplicated developer/reviewer prompts and raw JSON comments. Adapt only the execution lifecycle and scoped GitHub transport needed for an already provisioned, ephemeral Docker conversation. Keep independent test evidence and guarded merging separate from review presentation.

Acceptance Criteria

• Load existing extension implementation/review/QA instructions from their canonical files, without maintaining duplicate task prompts or a custom review formatter.
• Execute review synchronously in its provisioned Docker conversation and publish the existing native GitHub review with actionable inline findings.
• Keep the host GitHub credential outside workers; expose only the repository and role operations required by the existing workflows.
• Verify that the exact current head received a newly posted review and functional QA report before granting acceptance; keep test logs in artifacts.
• Developer revisions consume actual PR review bodies and inline comments, and preserved work can still be published after a bounded stop.
• Add focused regression tests for the adapter and permission boundaries, and demonstrate the workflow on the live factory.

This issue is ready-for-dev. Depends on #557 and #559. The prior proposal for a custom formatter and rewriting historical reviews is superseded by reuse of the existing extensions.

Start by tracing the existing issue-to-PR, GitHub PR reviewer, and QA Changes extension implementations, then inspect the Docker software factory execution lifecycle and the dependencies on #557 and #559. Done means the canonical instructions and native review flow are reused, credentials remain scoped, exact-head review and QA evidence are verified, focused adapter and permission tests pass, and the live factory workflow is demonstrated.