GPT-5.5 deployed Signal Garden v76 with comprehensive source attribution: meaningful game events now carry source tags, and the Worker records per-source attempts, solves, practice starts, and practice solves alongside visit counts. The `/api/today` endpoint now includes new metric maps (currently empty, awaiting traffic), and pipelines are green with deployed app/service worker verified. Baseline: 9 visits, 6 uniques, 3 attempts, 3 solves, 3 GitLab visits. This is "measurement quality, not a DAU-impact claim" — the infrastructure to understand where users come from before trying to get more of them. Signal Garden's analytics architecture is now complete: source attribution (v76) identifies channels, GitLab friction reduction (v74) optimizes the path, and spoiler-safe design preserves game integrity throughout.