🐛 Fix Prometheus alert parsing to include level-3 headers

The sed pattern '/^##/' was incorrectly matching both level-2 (##) and
level-3 (###) markdown headers, causing it to stop at "### Firing Alerts"
instead of continuing to "## Performance". This resulted in empty alert
sections even when alerts were present.

Changed pattern to '/^## /' (with space) to match only level-2 headers.

**Impact:**
- analyze-profiles.sh now correctly extracts and displays all alerts
- compare-profiles.sh now correctly detects alerts in both test runs

**Example:**
Before: "No Prometheus alerts detected" (incorrect)
After: Shows both pending alerts:
  - operator-controller-memory-growth: 132.4kB/sec
  - operator-controller-memory-usage: 107.9MB

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: tmshort

hack/tools/memory-profiling/analyze-profiles.sh

@@ -261,8 +261,9 @@ if [ -f "${OUTPUT_DIR}/e2e-summary.md" ]; then
 EOF
 
     # Extract the Alerts section from the markdown file
-    # Look for "## Alerts" section and extract until next ## section or end
-    ALERTS_SECTION=$(sed -n '/^## Alerts/,/^##/p' "${OUTPUT_DIR}/e2e-summary.md" | sed '$d' | tail -n +2)
+    # Look for "## Alerts" section and extract until next ## (level-2 header) section
+    # Note: Use '/^## /' with space to match level-2 headers only, not level-3 (###)
+    ALERTS_SECTION=$(sed -n '/^## Alerts/,/^## /p' "${OUTPUT_DIR}/e2e-summary.md" | sed '$d' | tail -n +2)
 
     if [ -n "${ALERTS_SECTION}" ] && [ "${ALERTS_SECTION}" != "None." ]; then
         cat >> "${REPORT_FILE}" << EOF

hack/tools/memory-profiling/compare-profiles.sh

@@ -289,7 +289,8 @@ EOF
 if [ -f "${TEST1_DIR}/e2e-summary.md" ] || [ -f "${TEST2_DIR}/e2e-summary.md" ]; then
     # Test 1 alerts
     if [ -f "${TEST1_DIR}/e2e-summary.md" ]; then
-        ALERTS1_SECTION=$(sed -n '/^## Alerts/,/^##/p' "${TEST1_DIR}/e2e-summary.md" | sed '$d' | tail -n +2)
+        # Use '/^## /' with space to match level-2 headers only, not level-3 (###)
+        ALERTS1_SECTION=$(sed -n '/^## Alerts/,/^## /p' "${TEST1_DIR}/e2e-summary.md" | sed '$d' | tail -n +2)
         if [ -n "${ALERTS1_SECTION}" ] && [ "${ALERTS1_SECTION}" != "None." ]; then
             ALERTS1="Present"
         else
@@ -301,7 +302,8 @@ if [ -f "${TEST1_DIR}/e2e-summary.md" ] || [ -f "${TEST2_DIR}/e2e-summary.md" ];
 
     # Test 2 alerts
     if [ -f "${TEST2_DIR}/e2e-summary.md" ]; then
-        ALERTS2_SECTION=$(sed -n '/^## Alerts/,/^##/p' "${TEST2_DIR}/e2e-summary.md" | sed '$d' | tail -n +2)
+        # Use '/^## /' with space to match level-2 headers only, not level-3 (###)
+        ALERTS2_SECTION=$(sed -n '/^## Alerts/,/^## /p' "${TEST2_DIR}/e2e-summary.md" | sed '$d' | tail -n +2)
         if [ -n "${ALERTS2_SECTION}" ] && [ "${ALERTS2_SECTION}" != "None." ]; then
             ALERTS2="Present"
         else