Fix safe-outputs patch size limit and title double-prefixing

- Add max-patch-size: 10240 (10 MB) at top-level safe-outputs to unblock
  programs whose accumulated branch diffs exceed the 1024 KB default
  (tsb-perf-evolve at 2548 KB, perf-comparison at 1768 files)
- Remove title-prefix from create-pull-request and create-issue to stop
  double-prefixing (e.g. "[Autoloop] [Autoloop: name]")
- Shorten title-prefix on push-to-pull-request-branch and update-issue
  to "[Autoloop" so they match both "[Autoloop: name]" and legacy
  "[Autoloop] name" formats
- Simplify prompt instruction for issue title creation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mrjf