fix: autosigning fields with direct links (#1696)

## Description

The changes in `sign-direct-template.tsx` automatically fill in field
values for text, number, and dropdown fields when default values are
present or if the fields are read-only. In `checkbox-field.tsx`, the
changes fix the checkbox signing by checking if the validation is met
and improving how it saves or removes checkbox choices.

## Testing Performed

I tested the code locally with a variety of documents/fields.

## Checklist

<!--- Please check the boxes that apply to this pull request. -->
<!--- You can add or remove items as needed. -->

- [x] I have tested these changes locally and they work as expected.
- [ ] I have added/updated tests that prove the effectiveness of these
changes.
- [ ] I have updated the documentation to reflect these changes, if
applicable.
- [x] I have followed the project's coding style guidelines.
- [ ] I have addressed the code review feedback from the previous
submission, if applicable.

apps/remix/app/components/general/direct-template/direct-template-signing-form.tsx

@@ -1,4 +1,4 @@
-import { useMemo, useState } from 'react';
+import { useEffect, useMemo, useState } from 'react';
 
 import { Trans } from '@lingui/react/macro';
 import type { Field, Recipient, Signature } from '@prisma/client';
@@ -170,6 +170,55 @@ export const DirectTemplateSigningForm = ({
     // Do not reset to false since we do a redirect.
   };
 
+  useEffect(() => {
+    const updatedFields = [...localFields];
+
+    localFields.forEach((field) => {
+      const index = updatedFields.findIndex((f) => f.id === field.id);
+      let value = '';
+
+      match(field.type)
+        .with(FieldType.TEXT, () => {
+          const meta = field.fieldMeta ? ZTextFieldMeta.safeParse(field.fieldMeta) : null;
+
+          if (meta?.success) {
+            value = meta.data.text ?? '';
+          }
+        })
+        .with(FieldType.NUMBER, () => {
+          const meta = field.fieldMeta ? ZNumberFieldMeta.safeParse(field.fieldMeta) : null;
+
+          if (meta?.success) {
+            value = meta.data.value ?? '';
+          }
+        })
+        .with(FieldType.DROPDOWN, () => {
+          const meta = field.fieldMeta ? ZDropdownFieldMeta.safeParse(field.fieldMeta) : null;
+
+          if (meta?.success) {
+            value = meta.data.defaultValue ?? '';
+          }
+        });
+
+      if (value) {
+        const signedValue = {
+          token: directRecipient.token,
+          fieldId: field.id,
+          value,
+        };
+
+        updatedFields[index] = {
+          ...field,
+          customText: value,
+          inserted: true,
+          signedValue,
+        };
+      }
+    });
+
+    setLocalFields(updatedFields);
+  }, []);
+
   return (
     <DocumentSigningRecipientProvider recipient={directRecipient}>
       <DocumentFlowFormContainerHeader title={flowStep.title} description={flowStep.description} />