Stage 0: org-contact custom fields (Food_Co_op_Organizing)

Adds four fields from the Organization Contact's Food_Co_op_Organizing
custom group to the Stage 0 (always-visible) section:

  Date Incorporated                (date, editable)
  Name on Incorporation Certificate (text, editable)
  Certificate of Incorporation     (readonly; see note)
  Equity share                     (currency, editable)

These live on the Organization Contact record, not on the Check-in
activity, so they read/write through a different code path:

  - FieldConfig gains civiContactField, mutually exclusive with civiField
  - /api/data extends the org Contact.get select to include them and
    merges values into the prefill payload keyed by form-side name
  - /api/submit splits incoming values: contact-bound fields go through
    Contact.update (run first), activity-bound fields stay in the
    Activity.create call (run second)
  - FieldRenderer readonly branch now detects file-shaped values
    ({id, file_name}) and displays the filename rather than [object Object]

Certificate_of_Incorporation is wired readonly only: the form's
file-upload pipeline is not actually wired end-to-end (FileList drops
at JSON.stringify in onSubmit; no /api/upload endpoint exists). A
follow-up will close that gap.

Also adds scripts/inspect-org-custom-fields.mjs, a one-off introspection
script for dumping CustomField metadata when wiring a new group.

config/form.ts

@@ -49,6 +49,11 @@ const G3 = "Stage_3";
 const G4 = "Stage_4";
 const G5 = "Stage_5";
 
+// Organization-contact custom group ("Food_Co_op_Organizing"). Fields here
+// live on the Organization Contact, not on the Check-in activity, so they
+// route through Contact.update on submit and Contact.get at form load.
+const G_ORG = "Food_Co_op_Organizing";
+
 // Stage 0 — Survey (always visible)
 const stage0: StageSectionConfig = {
   rank: 0,
@@ -86,6 +91,41 @@ const stage0: StageSectionConfig = {
       name: "contact_email",
       label: "Email",
       type: "readonly",
+    },
+    // Org-contact fields (Food_Co_op_Organizing custom group). These live
+    // on the Organization Contact record, not on the Check-in activity, so
+    // they read/write via Contact.get / Contact.update instead of the
+    // activity prefill walk.
+    {
+      name: "Date_Incorporated",
+      label: "Date Incorporated",
+      type: "date",
+      civiContactField: `${G_ORG}.Date_Incorporated`,
+      help: "The date this co-op was legally incorporated.",
+    },
+    {
+      name: "Name_on_Incorporation_Certificate",
+      label: "Name on Incorporation Certificate",
+      type: "text",
+      civiContactField: `${G_ORG}.Name_on_Incorporation_Certificate`,
+      help: "The legal name as it appears on the incorporation certificate.",
+    },
+    {
+      // Read-only until the form gains a file-upload pipeline. The field
+      // is shown as the prior attachment filename; fresh uploads aren't
+      // supported because /api/submit serializes as JSON (FileList drops).
+      name: "Certificate_of_Incorporation",
+      label: "Certificate of Incorporation",
+      type: "readonly",
+      civiContactField: `${G_ORG}.Certificate_of_Incorporation`,
+      help: "Contact staff to update the certificate on file.",
+    },
+    {
+      name: "Equity_share",
+      label: "Equity share",
+      type: "currency",
+      civiContactField: `${G_ORG}.Equity_share`,
+      help: "The cost of a single member-owner equity share.",
     },
 	  //     {
 	  //       name: "Peer_Group_Participation",