test(metrics): remove the query-name budget test

Summary

Removes TestNameBudget_CoversEveryDeclaredQueryName, the only test in internal/metrics/name_budget_test.go, and the file with it.

The test parsed the two query-name catalogs, internal/datastore/query_names.go and internal/storage/queries.go, and failed when the names they declare outgrew the name label budget in internal/metrics/cardinality.go.

Four sites named the test. Each one now describes the code this MR leaves behind:

Site	Change
internal/metrics/cardinality.go	The labelName comment drops the test and says the budget is raised by hand.
internal/datastore/query_names.go	The catalog doc comment drops the "checked by" clause.
docs/dev/database-query-patterns.md	The paragraph on the budget test now states that no test reads the catalogs.
.claude/skills/implement-step/SKILL.md	The merge gate runs go test ./internal/datastore/ alone, and the shared-registry section states that the budget shape has no assertion.

Both Go comment blocks sat above the comment caps, at 12 and 10 lines, grandfathered because no diff touched them. An edit pulls a block under its cap, so they are now 3 and 2 lines. The naming rules the longer block carried are already in docs/dev/database-query-patterns.md, which the short block points at.

Testing

go build ./..., go vet, go test ./internal/metrics/, and golangci-lint run pass on the touched packages. The full pre-commit chain passes, comment caps included.

This MR adds no behavior, so the e2e scenario catalogs in docs/testing/ need no entry.

Follow-up

#908 tracks what bounds the name label after this removal, and what a breach asks for. It carries the growth record, the series arithmetic, and the options.

Related to #908