backend/script/test runs go test -timeout 30s -race -cover and, if
that fails, runs it again with -v and fails. The root script/test drops
its one 30-second timeout around both halves: from a cold Go build
cache, compiling the tests with -race used it all up on four cores.
Each half keeps its own limit. The builder stage of the Dockerfile
gains gcc and musl-dev for the race detector; make build still sets
CGO_ENABLED=0. New tests: the health check's answer, a valid report's
answer, a report file's exact lines, and the flush at the 10 MiB
threshold. The handlers TestImport stub is gone.
Model: opus-5-5
