TODO.md workflow: branch from and merge into next (closes #137)

The "Workflow" list said to branch from main and to merge to main or open a pull request. It now says to branch from next, open a pull request that targets next, that the repository manager squash-merges a reviewed pull request into next, and that only sneak merges next into main, as the README does. The other items are unchanged. No other text in the repo contradicted the policy.

Docs only; merged under the docs-only rule without an adversarial review.

Model: opus-5-5
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>

TODO.md

@@ -1,12 +1,15 @@
 # Workflow
 
-- branch (from `main`)
+- branch from `next`
 - do the work in Next Step
 - move Next Step to the top of Completed Steps
 - move the top item of Future Steps into Next Step
 - commit (`TODO.md` changes in the same commit as the work)
-- merge to `main` if the branch is not protected, otherwise open a PR
 - push
+- open a pull request that targets `next`
+- once the pull request has passed review, the repository manager squash-merges
+  it into `next`
+- only sneak merges `next` into `main`
 
 # Status
 
@@ -22,6 +25,11 @@ declares one.
 
 # Completed Steps
 
+- 2026-09-29: The "Workflow" list at the top of this file now says to branch
+  from `next` and open a pull request that targets `next`, that the repository
+  manager squash-merges a reviewed pull request into `next`, and that only sneak
+  merges `next` into `main`, as the README does (issue 137).
+
 - 2026-09-29: The README's "Development workflow" and "For LLMs" sections now
   say work branches from `next`, every pull request targets `next`, the
   repository manager squash-merges reviewed pull requests into `next`, and only