Form: required submitter info section above the stage pathway

Captures the form-filler's name and email on every check-in. Both fields
are required; values write back to Check_in_data__organizing_.Survey_completed_by
and Survey_completed_by_email on the activity, giving us a per-submission
record of who filled out which check-in.

Implementation:
- config/form.ts: new submitterInfo section (rank -1) at the head of the
  sections array. rank -1 keeps it out of the past/current/future stage
  pathway computation.
- components/EngagementForm.tsx: filter the submitter section out of
  sectionsToRender and render it directly with FieldRenderer inside a
  bordered card above the stage list. The fields still flow through RHF
  registration, onInvalid scroll-to-error, and the onSubmit visibility
  filter the same as any other field.

The staff report auto-discovers these fields via CustomField.get since
they live in Check_in_data__organizing_, so the field history shows up
in the report with no extra wiring.

components/EngagementForm.tsx

@@ -19,6 +19,7 @@ function sectionForField(
 import { evaluate } from "@/lib/conditional";
 import { STAGE_OPTION_GROUP_ID } from "@/config/form";
 import { StageSection } from "./StageSection";
+import { FieldRenderer } from "./fields/FieldRenderer";
 import { loadDraft, saveDraft, clearDraft } from "@/lib/draft";
 
 interface EngagementFormProps {
@@ -241,6 +242,26 @@ export function EngagementForm({ config, cid, cs }: EngagementFormProps) {
 
   const currentRank = currentStageValue ? STAGE_RANK[currentStageValue] ?? 0 : 0;
 
+  // Section pathway state — past / current / future is determined entirely
+  // by stage rank vs the org's current rank. Sections never hide; future
+  // stages render in a locked treatment so users can preview what's ahead.
+  //
+  // Section-level visibleWhen is still consulted on submit to strip
+  // locked-stage values from the payload (see onSubmit below), so a future
+  // stage's data never gets accidentally written.
+  // The submitter-info section (rank: -1) lives outside the stage pathway —
+  // it renders directly above the section list (see JSX below), not inside
+  // the rail/marker accordion model used for Stage 0..5. Filter it out here
+  // so its rank doesn't pollute the past/current/future calculation.
+  const submitterSection = useMemo(
+    () => config.sections.find((s) => s.id === "submitter_info"),
+    [config.sections],
+  );
+  const stageSections = useMemo(
+    () => config.sections.filter((s) => s.id !== "submitter_info"),
+    [config.sections],
+  );
+
   // Section pathway state — past / current / future is determined entirely
   // by stage rank vs the org's current rank. Sections never hide; future
   // stages render in a locked treatment so users can preview what's ahead.
@@ -250,12 +271,12 @@ export function EngagementForm({ config, cid, cs }: EngagementFormProps) {
   // stage's data never gets accidentally written.
   const sectionsToRender = useMemo(
     () =>
-      config.sections.map((s) => {
+      stageSections.map((s) => {
         const pathwayState: PathwayState =
           s.rank < currentRank ? "past" : s.rank === currentRank ? "current" : "future";
         return { section: s, pathwayState, locked: pathwayState === "future" };
       }),
-    [config.sections, currentRank],
+    [stageSections, currentRank],
   );
 
   // Track which sections the user has manually opened/closed so we can
@@ -398,6 +419,38 @@ export function EngagementForm({ config, cid, cs }: EngagementFormProps) {
         }} />
       )}
 
+      {submitterSection && (
+        <section
+          aria-labelledby="submitter-info-heading"
+          className="rounded-2xl border border-rule bg-paper p-4 sm:p-5"
+        >
+          <h2
+            id="submitter-info-heading"
+            className="font-display text-lg font-medium text-ink"
+          >
+            {submitterSection.label}
+          </h2>
+          {submitterSection.intro && (
+            <p className="mt-1 text-sm text-ink-soft">{submitterSection.intro}</p>
+          )}
+          <div className="mt-3 grid grid-cols-1 gap-4 sm:grid-cols-2">
+            {submitterSection.fields.map((f) => (
+              <FieldRenderer
+                key={f.name}
+                field={f}
+                register={register}
+                setValue={setValue}
+                control={control}
+                errors={errors}
+                cid={cid}
+                cs={cs}
+                onUploadStateChange={handleUploadStateChange}
+              />
+            ))}
+          </div>
+        </section>
+      )}
+
       <ol className="relative space-y-5 md:pl-12">
         {sectionsToRender.map((entry, i) => {
           const { section, pathwayState, locked } = entry;