Correct the Workers Builds branch control note

[patshone-gsl]

BUGFIX
Documentation-only. Earlier guidance in MIGRATION-NOTES.md and PR #13 said to exclude documentation, 3.9 and release/* from Workers Builds triggers. That capability does not exist, so the note would have sent the next person looking for a setting that isn't there.

Docs

Jira - none. Documentation correction; branch named descriptively.

Solution overview

Root cause

Workers Builds branch control (Overview → Worker → Settings → Build → Branch control) offers only a production-branch dropdown and a single all-or-nothing checkbox for non-production branches. There is no per-branch include or exclude list.

Fix

Records what the setting actually offers, that non-production builds are currently enabled — evidenced by two feature-branch pushes each producing a versions upload with no deployment — and that the documentation problem is therefore live rather than hypothetical.

Also records that there is no clean mitigation: the build fails at npm ci before any command we control runs, and a package.json cannot be added to documentation because GitBook owns that branch.

Recommendation captured: disable non-production branch builds, on alarm-fatigue grounds rather than noise — a real failure on main would be lost among constant documentation failures. Preview URLs are convenient for the Phase 4 look-and-feel review but not required, since scripts/screenshots.mjs works against a local dev server.

Breaking changes

None. Documentation only.