Two stale doc lines still describe get_memory_trend's total_granted_mb as an always-0 parity placeholder #3549

After #3529 (null + granted_note, both SKUs), two documentation lines still describe the old behavior:

• Darling/README.md:542 — "get_memory_trend carries a total_granted_mb field for field-for-field parity with Lite, where its memory_stats-only read leaves it 0 (the grant overlay is a separate chart series)."
• Darling/PerformanceMonitor.Darling.Service/Mcp/DarlingTrendReader.cs:44 — doc comment: "minus its always-0 TotalGrantedMb overlay field, which the tool carries as a Lite parity ..."

Both should say the field is an explicit null and the envelope's granted_note points at get_memory_grants. One-line fixes each; they sat outside the #3529 PR's file boundary.