test: add bats test suite for lib/ helper scripts

110 tests across 10 test files covering all lib/ scripts:
- archeflow-event.sh: JSONL format, seq numbering, parent fields, validation
- archeflow-memory.sh: add/list/decay/forget/inject/extract commands
- archeflow-git.sh: branch creation, commit format, merge strategies, safety
- archeflow-report.sh: markdown output, summary mode, in-progress handling
- archeflow-progress.sh: progress.md generation, JSON mode, error handling
- archeflow-score.sh: archetype scoring, effectiveness report, validation
- archeflow-dag.sh: DAG rendering, color flags, tree structure
- archeflow-rollback.sh: arg parsing, phase validation, mutual exclusivity
- archeflow-init.sh: template listing, clone from project, arg validation
- archeflow-review.sh: diff modes, stats, branch/commit range review

Includes test_helper.bash (shared setup/teardown with temp git repos)
and scripts/run-tests.sh runner.

scripts/run-tests.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+# run-tests.sh — Run all ArcheFlow bats tests.
+#
+# Usage: ./scripts/run-tests.sh [bats-args...]
+# Examples:
+#   ./scripts/run-tests.sh                  # Run all tests
+#   ./scripts/run-tests.sh --filter "event" # Run only event tests
+#   ./scripts/run-tests.sh -t               # TAP output
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
+TESTS_DIR="$PROJECT_DIR/tests"
+
+# Find bats binary
+BATS="${BATS:-}"
+if [[ -z "$BATS" ]]; then
+  if command -v bats &>/dev/null; then
+    BATS="bats"
+  elif [[ -x "$HOME/.local/bin/bats" ]]; then
+    BATS="$HOME/.local/bin/bats"
+  else
+    echo "ERROR: bats not found. Install bats-core or set BATS env var." >&2
+    exit 1
+  fi
+fi
+
+echo "Running ArcheFlow tests..."
+echo "  bats: $($BATS --version)"
+echo "  tests: $TESTS_DIR"
+echo ""
+
+exec "$BATS" "$@" "$TESTS_DIR"/*.bats