Groups are inferred, not configured

This page argues that the dullest possible grouping rule beats a configured one, and that where the names come from matters more than how they are split.

Runners and repos are grouped so that app-ios, app-web and app-backend appear under one app heading. Nothing configures this: a repo name is split on -, _ and ., and any first token shared by two or more repos becomes a group. Repos that share nothing with anything land under other.

The rule is the dullest one that works. Run against a real 34-repo fleet it produced exactly the groups a person would have drawn by hand, and raising the threshold from two to three changed none of them — so there is no cleverness here to go wrong later.

The names come from disk and from SQLite, never from the current tick. This is the whole reason the corpus is assembled the way it is. Groups derived from one tick's API results dissolve the moment a call fails, and a heading that disappears and comes back moves every tile beneath it — the same class of failure the drift rules already guard against, where a single 503 once produced a 46-second phantom orphan alert. Verified by running the collector with every GitHub call returning 401: the grouping came out byte-identical to a healthy run.

Only repos the fleet has something to do with get a vote — those with a workflow or a runner, the same test the roster uses. An account full of boilerplates and tutorial checkouts otherwise decides the layout: two unrelated repos that happened to begin github- were enough to invent a github heading.

Four escape hatches, all optional and all off by default: FLEET_PROJECTS pins groups and their order, FLEET_GROUP_IGNORE suppresses a token that is shared by accident rather than convention, FLEET_GROUP_MIN moves the threshold, and FLEET_GROUPS=off gives one flat list. Pins are matched as prefixes rather than tokens, which is how FLEET_PROJECTS behaved when it was the only mechanism — so upgrading cannot silently regroup a dashboard someone had already arranged.

All four are documented in Grouping variables.