PR titles that said Permissions and meant a real feature

The Broader Goal at the End of the Previous PR

The #1435 open-PR sweep closed a pile of fix: ## Permissions (job-…) siblings whose code had already merged. The remaining goalpost was the product bug that produced those titles: #1427 (and the same fingerprint on #1421).

Strategic Shifts in This PR

None. The #1435 comment already named the mechanism: Agy dispatch prepends ## Permissions plus a bullet list to the stored task, and auto-finalize takes splitlines()[0] as the PR title and body Task: line.

What This PR Shipped

_task_summary_line() skips injected markdown sections (## Permissions, plus the other known dispatch headings) and their following list items, then uses the first remaining line. _commit_subject_for_job and _maybe_open_worktree_pr both use it. Agy still receives the permissions block first in the prompt (test_dispatch_agent_injects_agy_permissions_header unchanged).

Brainstorm Visuals Used

None.

What This Achieved on the Path to Autonomy

Reviewers can tell Agy auto-PRs apart without opening each one. Combined with the #1435 sibling closures, the ## Permissions cluster should not grow.

Strategic Note: The Goal at the End of This PR

#1427/#1421 closed. #1446 (pr-check sandbox write + pytest -k) is the remaining review-dispatch hygiene item.