Rewrite script/test to the canonical race-enabled pattern (closes #67)

script/test now runs `go test -timeout 30s -race -cover ./...`, quiet on
success and rerunning verbose with `exit 1` on failure, per policy.

-race surfaced a real data race on the process-global apex/log logger:
Init reconfigures it (SetHandler/SetLevel) each CLI run while other
goroutines read it to log. internal/log now mutates the global under the
write lock and reads it under the read lock (new emit helper, DebugReal),
and drops WithError, whose returned Entry logged outside that lock.

That Entry was also the only thing printing a failed command's error to
stderr, so run() now reports it via log.Errorf (shown under -q too).

The corruption fuzz test shrinks (20000->1500 files, 500->100 iters) to
keep the suite under 20s with -race.

Model: opus-4-8

TODO.md

@@ -24,6 +24,9 @@ only thing left of the `chore/align-repo-policies` branch is the list below.
 
 # Completed Steps
 
+- 2026-09-21: rewrote `script/test` to the canonical pattern (30s timeout,
+  `-race -cover`, quiet-first with verbose-on-failure rerun) and fixed the
+  process-global logger data race it surfaced (#67)
 - 2026-09-21: added the canonical `.editorconfig`, made `.gitignore` cover
   secrets, OS, editor, and Go artifacts, and removed the dead Drone CI
   references from `.gitignore` and `bin/gitrev.sh` (#72)
@@ -65,7 +68,6 @@ only thing left of the `chore/align-repo-policies` branch is the list below.
     - Move FORMAT.md from repo root to docs/ and update the AGENTS.md reference
     - Pin Makefile-installed Go tools (`protoc-gen-go@v1.28.1`,
       `golangci-lint@v2.12.2`) by module hash, not mutable tag
-    - Set `make test` timeout to 30s (currently 10s)
     - Add explicit README "Rationale" heading (content exists under other
       names); name the author in the README Description first line
     - Reconcile root-level AGENTS.md with directory-hygiene policy (keep or