chore(test): remove time log, keep only baseline

Time log adds noise to git history without practical benefit.
The baseline file alone is sufficient for the pre-commit time guard.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: claude

.githooks/checks/02-unit-tests.sh

@@ -1,23 +1,19 @@
 #!/bin/sh
 # L1: unit tests — fast, no external deps, no Docker.
 #
-# Time guard: each successful run is appended to .test-time-log and the
-# elapsed time is compared against .test-time-baseline. Both files are
-# committed so the history is visible and shared.
+# Time guard: elapsed seconds are compared against .test-time-baseline.
+# The baseline file is committed so the reference survives machine changes.
 #
-# .test-time-baseline  — last recorded elapsed time (seconds), updated on
-#                        every pass. Fail if current > baseline * 1.5.
-# .test-time-log       — append-only history: one line per run, format:
-#                          ISO8601  elapsed_s  git_sha  branch
+# .test-time-baseline  — last recorded elapsed time (seconds). Updated on
+#                        every passing run. Fail if current > baseline * 1.5.
 #
-# To reset the baseline after intentional perf change:
+# To reset after an intentional perf change:
 #   echo <new_seconds> > .test-time-baseline
-#   git add .test-time-baseline .test-time-log && git commit -m "perf: reset test baseline"
+#   git add .test-time-baseline && git commit -m "perf: reset test baseline"
 
 REPO="$(git rev-parse --show-toplevel)"
 LOG_FILE="${REPO}/.test-fail.log"
 BASELINE_FILE="${REPO}/.test-time-baseline"
-TIMELOG_FILE="${REPO}/.test-time-log"
 rm -f "$LOG_FILE"
 
 echo "pre-commit: running unit tests..."
@@ -36,12 +32,6 @@ END=$(date +%s)
 ELAPSED=$((END - START))
 rm -f "$LOG_FILE"
 
-# Append to time log.
-SHA=$(git rev-parse --short HEAD 2>/dev/null || echo "unknown")
-BRANCH=$(git rev-parse --abbrev-ref HEAD 2>/dev/null || echo "unknown")
-TS=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
-printf "%s\t%ss\t%s\t%s\n" "$TS" "$ELAPSED" "$SHA" "$BRANCH" >> "$TIMELOG_FILE"
-
 # Time guard: compare against last successful run.
 if [ -f "$BASELINE_FILE" ]; then
     BASELINE=$(cat "$BASELINE_FILE")
@@ -52,14 +42,11 @@ if [ -f "$BASELINE_FILE" ]; then
         echo "  Current:  ${ELAPSED}s" >&2
         echo "  Baseline: ${BASELINE}s  (limit: ${THRESHOLD}s = baseline × 1.5)" >&2
         echo "" >&2
-        tail -10 "$TIMELOG_FILE" | awk -F'\t' '{printf "  %s\t%s\n", $1, $2}' >&2
-        echo "" >&2
         echo "To reset: echo ${ELAPSED} > .test-time-baseline" >&2
         exit 1
     fi
 fi
 
-# Update baseline to the current run so the guard tracks recent history.
+# Update baseline to current run time.
 echo "$ELAPSED" > "$BASELINE_FILE"
-
 echo "pre-commit: unit tests passed (${ELAPSED}s)."