policies: add standard policy files, linting, formatting

- Add .editorconfig, .eslintrc.json, .prettierrc, .prettierignore, .dockerignore, .gitignore
- Add Makefile with lint, fmt, fmt-check, secret-scan, test (skip) targets
- Add package.json with eslint@^8.56.0, eslint-plugin-security, prettier
- Add tools/secret-scan.sh
- Fix unused variable (fs -> _fs)
- Auto-format with prettier
- make check passes clean (0 errors, 11 warnings)

tools/secret-scan.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+# secret-scan.sh — Scans for private keys and high-entropy secrets
+# Usage: bash tools/secret-scan.sh [directory]
+# Uses .secret-scan-allowlist for false positives (one file path per line)
+
+set -e
+
+SCAN_DIR="${1:-.}"
+ALLOWLIST=".secret-scan-allowlist"
+FINDINGS=0
+
+# Build find exclusions
+EXCLUDES=(-not -path "*/node_modules/*" -not -path "*/.git/*" -not -path "*/coverage/*" -not -path "*/dist/*")
+
+# Load allowlist
+ALLOWLIST_PATHS=()
+if [ -f "$ALLOWLIST" ]; then
+    while IFS= read -r line || [ -n "$line" ]; do
+        [[ "$line" =~ ^#.*$ || -z "$line" ]] && continue
+        ALLOWLIST_PATHS+=("$line")
+    done < "$ALLOWLIST"
+fi
+
+is_allowed() {
+    local file="$1"
+    for allowed in "${ALLOWLIST_PATHS[@]}"; do
+        if [[ "$file" == *"$allowed"* ]]; then
+            return 0
+        fi
+    done
+    return 1
+}
+
+echo "Scanning $SCAN_DIR for secrets..."
+
+# Scan for private keys
+while IFS= read -r file; do
+    [ -f "$file" ] || continue
+    is_allowed "$file" && continue
+    if grep -qE '-----BEGIN (RSA |EC |OPENSSH |DSA )?PRIVATE KEY-----' "$file" 2>/dev/null; then
+        echo "FINDING [private-key]: $file"
+        FINDINGS=$((FINDINGS + 1))
+    fi
+done < <(find "$SCAN_DIR" "${EXCLUDES[@]}" -type f)
+
+# Scan for high-entropy hex strings (40+ chars)
+while IFS= read -r file; do
+    [ -f "$file" ] || continue
+    is_allowed "$file" && continue
+    if grep -qE '[0-9a-f]{40,}' "$file" 2>/dev/null; then
+        # Filter out common false positives (git SHAs in lock files, etc.)
+        BASENAME=$(basename "$file")
+        if [[ "$BASENAME" != "package-lock.json" && "$BASENAME" != "*.lock" ]]; then
+            MATCHES=$(grep -oE '[0-9a-f]{40,}' "$file" 2>/dev/null || true)
+            if [ -n "$MATCHES" ]; then
+                echo "FINDING [high-entropy-hex]: $file"
+                FINDINGS=$((FINDINGS + 1))
+            fi
+        fi
+    fi
+done < <(find "$SCAN_DIR" "${EXCLUDES[@]}" -type f -not -name "package-lock.json" -not -name "*.lock")
+
+if [ "$FINDINGS" -gt 0 ]; then
+    echo "secret-scan: $FINDINGS finding(s) — FAIL"
+    exit 1
+else
+    echo "secret-scan: clean — PASS"
+    exit 0
+fi