Address code review findings across relay, UI, and Go backend

- relay: key uploadables map by actual variable name instead of iteration
  index so order-mismatch between Object.keys passes can't desync the
  multipart map from form field names
- mcp/v1: drop dead commented middleware line
- DurationPicker: tighten parse regex to require PT prefix for M/H and P
  for D/W, and reject NaN in stringify so cleared inputs don't produce
  invalid duration strings

Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>

packages/ui/src/Molecules/DurationPicker/DurationPicker.tsx

@@ -26,7 +26,7 @@ type Props = {
 } & HTMLAttributes<HTMLInputElement>;
 
 const stringify = (value: number | null, unit: string): string | null => {
-  if (value === null || value <= 0) return null;
+  if (value === null || !Number.isFinite(value) || value <= 0) return null;
 
   switch (unit) {
     case "M":
@@ -43,10 +43,10 @@ const stringify = (value: number | null, unit: string): string | null => {
 };
 
 const parse = (value: string): { amount: number; unit: string } => {
-  const match = value.match(/PT?(\d+)([MDWH])/);
+  const match = value.match(/^P(?:T(\d+)([MH])|(\d+)([DW]))$/);
   if (!match) return { amount: 0, unit: "D" };
-  const amount = parseInt(match[1], 10) || 0;
-  const unit = match[2];
+  const amount = parseInt(match[1] ?? match[3] ?? "0", 10) || 0;
+  const unit = match[2] ?? match[4] ?? "D";
   if (amount % 7 === 0 && unit === "D") {
     return { amount: amount / 7, unit: "W" };
   }