feat(water-log): surface irrigator name on log form + success screen

Makes the currently-signed-in irrigator visible while data is being
entered and confirmed, so the operator can verify the reading is
attributed to them at a glance.

  - LogForm nav bar: title + initials avatar + name as a subtitle,
    sign-out button moves from the form footer into the nav bar
    (more discoverable, frees vertical space for the Submit button)
  - SuccessScreen recap: 'Logged by {name}' row with avatar below
    the timestamp, matches the log form styling
  - MobileWaterApp threads irrigatorName through to both screens

The headgate list still shows 'Signed in as {name}' as a small
caption — left untouched to avoid duplicate UI.

Validation:
  - tsc --noEmit clean
  - eslint clean on all modified files

src/components/water/mobile/LogForm.tsx

@@ -34,7 +34,7 @@ import {
 import { SegmentedControl } from "./SegmentedControl";
 import type { FieldHeadgate, MobileUnit } from "./types";
 import { MOBILE_UNITS } from "./types";
-import { ChevronLeft, Clock, Gauge, Pencil, Pin, Spinner } from "./icons";
+import { ChevronLeft, Clock, Gauge, Logout, Pencil, Pin, Spinner } from "./icons";
 import {
   formatLongTimestamp,
   formatMeasurement,
@@ -43,6 +43,7 @@ import {
 
 type Props = {
   headgate: FieldHeadgate;
+  irrigatorName?: string;
   onSubmit: (input: { measurement: number; unit: string; notes: string }) => Promise<void>;
   onChangeHeadgate: () => void;
   onLogout: () => void;
@@ -54,6 +55,7 @@ const NOTES_MAX = 500;
 
 export function MobileWaterLogForm({
   headgate,
+  irrigatorName,
   onSubmit,
   onChangeHeadgate,
   onLogout,
@@ -137,10 +139,9 @@ export function MobileWaterLogForm({
     >
       {/* ── Top nav ────────────────────────────────────────────── */}
       <header
-        className="sticky top-0 z-30 flex h-11 items-center border-b border-[rgba(60,60,67,0.12)] bg-[rgba(255,255,255,0.85)] px-2"
+        className="sticky top-0 z-30 flex items-center gap-2 border-b border-[rgba(60,60,67,0.12)] bg-[rgba(255,255,255,0.85)] px-2 py-2"
         style={{
-          paddingTop: "env(safe-area-inset-top)",
-          height: "calc(44px + env(safe-area-inset-top))",
+          paddingTop: "calc(env(safe-area-inset-top) + 4px)",
           backdropFilter: "blur(20px) saturate(180%)",
           WebkitBackdropFilter: "blur(20px) saturate(180%)",
         }}
@@ -149,12 +150,14 @@ export function MobileWaterLogForm({
           type="button"
           onClick={onChangeHeadgate}
           aria-label="Back to headgates"
-          className="flex h-9 w-9 items-center justify-center rounded-full text-[#14532d] active:bg-[rgba(120,120,128,0.16)]"
+          className="flex h-9 w-9 shrink-0 items-center justify-center rounded-full text-[#14532d] active:bg-[rgba(120,120,128,0.16)]"
         >
           <ChevronLeft size={22} />
         </button>
+
+        <div className="min-w-0 flex-1">
           <h1
-          className="absolute left-1/2 -translate-x-1/2 text-[17px] font-semibold text-[#1d1d1f]"
+            className="truncate text-[17px] font-semibold leading-[1.15] text-[#1d1d1f]"
             style={{
               fontFamily:
                 "-apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', Roboto, sans-serif",
@@ -162,7 +165,27 @@ export function MobileWaterLogForm({
           >
             Log Reading
           </h1>
-        <span className="w-9" />
+          {irrigatorName ? (
+            <div className="mt-0.5 flex items-center gap-1.5 truncate text-[12px] text-[rgba(60,60,67,0.6)]">
+              <span
+                aria-hidden
+                className="inline-flex h-4 w-4 shrink-0 items-center justify-center rounded-full bg-[#14532d] text-[9px] font-bold uppercase text-white"
+              >
+                {initials(irrigatorName)}
+              </span>
+              <span className="truncate">{irrigatorName}</span>
+            </div>
+          ) : null}
+        </div>
+
+        <button
+          type="button"
+          onClick={onLogout}
+          aria-label="Sign out"
+          className="flex h-9 w-9 shrink-0 items-center justify-center rounded-full text-[#14532d] active:bg-[rgba(120,120,128,0.16)]"
+        >
+          <Logout size={20} />
+        </button>
       </header>
 
       {/* ── Scrollable form body ───────────────────────────────── */}
@@ -352,15 +375,6 @@ export function MobileWaterLogForm({
               </>
             )}
           </button>
-          <div className="mt-2 flex items-center justify-center">
-            <button
-              type="button"
-              onClick={onLogout}
-              className="text-[12px] font-medium text-[rgba(60,60,67,0.45)] active:text-[#14532d]"
-            >
-              Sign out
-            </button>
-          </div>
         </div>
       </form>
     </div>
@@ -377,4 +391,16 @@ function SectionHeader({ children }: { children: React.ReactNode }) {
   );
 }
 
+/**
+ * Two-letter initials for the avatar chip in the nav bar. "Tyler
+ * Smith" → "TS", "Maria" → "MA". Falls back to "?" when there's no
+ * usable name.
+ */
+function initials(name: string): string {
+  const parts = name.trim().split(/\s+/).filter(Boolean);
+  if (parts.length === 0) return "?";
+  if (parts.length === 1) return parts[0].slice(0, 2).toUpperCase();
+  return (parts[0][0] + parts[parts.length - 1][0]).toUpperCase();
+}
+
 export default MobileWaterLogForm;

src/components/water/mobile/MobileWaterApp.tsx

@@ -213,6 +213,7 @@ export function MobileWaterApp() {
         <MobileWaterLogForm
           key={`${selectedHeadgate.id}-${logFormKey}`}
           headgate={selectedHeadgate}
+          irrigatorName={irrigatorName ?? undefined}
           onSubmit={handleLogSubmit}
           onChangeHeadgate={handleBackToHeadgates}
           onLogout={handleLogout}
@@ -230,6 +231,7 @@ export function MobileWaterApp() {
           measurement={submittedLog.measurement}
           unit={submittedLog.unit}
           timestamp={submittedLog.timestamp}
+          irrigatorName={irrigatorName ?? undefined}
           onLogAnother={handleLogAnother}
           onBackToHeadgates={handleBackToHeadgates}
         />

src/components/water/mobile/SuccessScreen.tsx

@@ -26,6 +26,9 @@ type Props = {
   measurement: number;
   unit: string;
   timestamp: Date;
+  /** Name of the irrigator who logged the entry — shown in the recap
+   *  so the operator can confirm the reading is attributed to them. */
+  irrigatorName?: string;
   onLogAnother: () => void;
   onBackToHeadgates: () => void;
 };
@@ -35,6 +38,7 @@ export function MobileWaterSuccessScreen({
   measurement,
   unit,
   timestamp,
+  irrigatorName,
   onLogAnother,
   onBackToHeadgates,
 }: Props) {
@@ -197,6 +201,17 @@ export function MobileWaterSuccessScreen({
             <div className="mt-2 border-t border-[rgba(60,60,67,0.10)] pt-2 text-[12px] text-[rgba(60,60,67,0.45)]">
               {formatLongTimestamp(timestamp)}
             </div>
+            {irrigatorName ? (
+              <div className="mt-1.5 flex items-center gap-1.5 text-[12px] text-[rgba(60,60,67,0.55)]">
+                <span
+                  aria-hidden
+                  className="inline-flex h-4 w-4 shrink-0 items-center justify-center rounded-full bg-[#14532d] text-[9px] font-bold uppercase text-white"
+                >
+                  {initials(irrigatorName)}
+                </span>
+                <span>Logged by {irrigatorName}</span>
+              </div>
+            ) : null}
           </div>
 
           {/* Action buttons */}
@@ -248,3 +263,15 @@ export function MobileWaterSuccessScreen({
 }
 
 export default MobileWaterSuccessScreen;
+
+/**
+ * Two-letter initials for the avatar chip in the recap.
+ * Mirrors the same helper used in the log form header so the avatar
+ * stays consistent across the two screens.
+ */
+function initials(name: string): string {
+  const parts = name.trim().split(/\s+/).filter(Boolean);
+  if (parts.length === 0) return "?";
+  if (parts.length === 1) return parts[0].slice(0, 2).toUpperCase();
+  return (parts[0][0] + parts[parts.length - 1][0]).toUpperCase();
+}