Remove rebase requirement before opening PR (#6479)

Author: juliusmarminge

AGENTS.md

@@ -114,7 +114,6 @@ An empty database is a bad test. Seed your worktree's `.t3` with a copy of real
 - Never make a PR unless the developer explicitly asks you to do so.
 - Conventional commit titles, plain language: `fix(web): new threads no longer spike CPU`.
 - Body: the problem in a sentence or two, then how you fixed it. End with the model and harness that did the work.
-- **Rebase onto latest main before opening.** Stale branches conflict and burn a review round.
 - UI changes need before/after images. Motion or timing needs a short video.
 - One concern per PR. If the description says "also", split it.
 - When babysitting: poll checks and comments newer than the last push, verify each bot finding against the source, fix real ones, dismiss false positives with a written reason. Stay quiet when nothing is new. Stop when the bots are green on the latest commit.