Fix: Multiple benchmark script bugs

- benchmark_network.sh:
  - Removed info() call in run_fastsync that contaminated output parsing
  - Reduced excessive wait times (was up to 66s for WAN)
  - More reasonable dynamic wait based on latency
- compare_rsync.sh:
  - Fixed hardcoded -n 4 connections, now accepts connection count parameter
  - Replaced slow md5sum verification with fast file count+size check
  - Added latency-aware wait times for 1 connection
- benchmark.sh:
  - Added sync after client to ensure disk writes complete
  - Added EXIT trap for tc netem cleanup and process cleanup
  - Removed duplicate manual cleanup
- benchmark_comprehensive.sh:
  - Added latency-aware wait times for 1 connection in run_fastsync
  - Added documentation note that rsync/cp bypass tc netem (use benchmark_network.sh for fair TCP comparison)

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

benchmark_network.sh

@@ -232,21 +232,22 @@ run_fastsync() {
     local output
     output=$(timeout 300 "$CLIENT_BIN" -h "$HOST" -p "$port" -s "$SRC_DIR" -n "$nconn" 2>&1) || true
     
-    # With network latency, wait longer for all data to be written and synced to disk
-    # Scale wait time based on latency: base wait + (latency factor * connection count factor)
-    # 1 connection needs significantly more time under high latency
-    local base_wait=$(( LATENCY_MS * 2 / 10 ))
-    local conn_factor=$(( 16 / nconn ))
-    local wait_time=$(( base_wait + conn_factor + 5 ))
-    [ "$wait_time" -lt 10 ] && wait_time=10
-    [ "$nconn" -eq 1 ] && wait_time=$(( wait_time + LATENCY_MS / 5 + 5 ))
+    # With network latency, wait for all data to be written and synced to disk
+    # Base wait: proportional to latency (round-trip * 2 for safety margin)
+    # Connection factor: more connections = faster transfer = less extra wait needed
+    # 1 connection needs more time as data is sent sequentially
+    local base_wait=$(( LATENCY_MS / 10 ))
+    [ "$base_wait" -lt 2 ] && base_wait=2
+    local conn_factor=$(( 10 / nconn ))
+    local wait_time=$(( base_wait + conn_factor + 3 ))
+    [ "$wait_time" -lt 5 ] && wait_time=5
+    [ "$nconn" -eq 1 ] && wait_time=$(( wait_time + LATENCY_MS / 20 + 3 ))
     
-    info "Waiting ${wait_time}s for sync to complete..."
     sleep $wait_time
     kill "$spid" 2>/dev/null || true
     wait "$spid" 2>/dev/null || true
     sync
-    sleep 2
+    sleep 1
     sync
     
     local ms=$(echo "$output" | grep -oP 'ms=\K[0-9.]+' || echo "0")