feat: add pub.leaflet.pages.linearDocument to longDescription union

Insert pub.leaflet.pages.linearDocument#main as the second variant in
the longDescription union, between descriptionString and strongRef,
so clients can embed a Leaflet document directly rather than only via
a strongRef indirection.

Also fix the style checker to skip ref-resolution for known-external
namespaces (pub.leaflet.*, app.bsky.*, com.atproto.*) in union types,
consistent with how file-level checks already exempt those namespaces.

Author: satyam-mishra-pce

SCHEMAS.md

@@ -424,13 +424,15 @@ A location represented as a string, e.g. coordinates or a small GeoJSON string.
 
 #### Properties
 
-| Property           | Type       | Required | Description                                                                                                                                                                                                                                    | Comments      |
-| ------------------ | ---------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------- |
-| `organizationType` | `string[]` | ❌       | Legal or operational structures of the organization (e.g. 'nonprofit', 'ngo', 'government', 'social-enterprise', 'cooperative').                                                                                                               | maxLength: 10 |
-| `urls`             | `ref[]`    | ❌       | Additional reference URLs (social media profiles, contact pages, donation links, etc.) with a display label for each URL.                                                                                                                      |               |
-| `location`         | `ref`      | ❌       | A strong reference to the location where the organization is based. The record referenced must conform with the lexicon app.certified.location.                                                                                                |               |
-| `foundedDate`      | `string`   | ❌       | When the organization was established. Stored as datetime per ATProto conventions (no date-only format exists). Clients should use midnight UTC (e.g., '2005-01-01T00:00:00.000Z'); consumers should treat only the date portion as canonical. |               |
-| `createdAt`        | `string`   | ✅       | Client-declared timestamp when this record was originally created.                                                                                                                                                                             |               |
+| Property           | Type       | Required | Description                                                                                                                                                                                                                                                    | Comments                           |
+| ------------------ | ---------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------- |
+| `organizationType` | `string[]` | ❌       | Legal or operational structures of the organization (e.g. 'nonprofit', 'ngo', 'government', 'social-enterprise', 'cooperative').                                                                                                                               | maxLength: 10                      |
+| `urls`             | `ref[]`    | ❌       | Additional reference URLs (social media profiles, contact pages, donation links, etc.) with a display label for each URL.                                                                                                                                      |                                    |
+| `location`         | `ref`      | ❌       | A strong reference to the location where the organization is based. The record referenced must conform with the lexicon app.certified.location.                                                                                                                |                                    |
+| `foundedDate`      | `string`   | ❌       | When the organization was established. Stored as datetime per ATProto conventions (no date-only format exists). Clients should use midnight UTC (e.g., '2005-01-01T00:00:00.000Z'); consumers should treat only the date portion as canonical.                 |                                    |
+| `longDescription`  | `union`    | ❌       | Long-form description of the organization, such as its mission, history, or detailed project narrative. An inline string for plain text or markdown, a Leaflet linear document record embedded directly, or a strong reference to an existing document record. |                                    |
+| `visibility`       | `string`   | ❌       | Controls whether the organization or project is publicly discoverable on platforms that honor this setting.                                                                                                                                                    | Known values: `public`, `unlisted` |
+| `createdAt`        | `string`   | ✅       | Client-declared timestamp when this record was originally created.                                                                                                                                                                                             |                                    |
 
 #### Defs
 

lexicons/app/certified/actor/organization.json

@@ -42,9 +42,10 @@
             "type": "union",
             "refs": [
               "org.hypercerts.defs#descriptionString",
+              "pub.leaflet.pages.linearDocument#main",
               "com.atproto.repo.strongRef"
             ],
-            "description": "Long-form description of the organization, such as its mission, history, or detailed project narrative. An inline string for plain text or markdown, or a strong reference to a rich-text document record (e.g. a Leaflet linear document)."
+            "description": "Long-form description of the organization, such as its mission, history, or detailed project narrative. An inline string for plain text or markdown, a Leaflet linear document record embedded directly, or a strong reference to an existing document record."
           },
           "visibility": {
             "type": "string",

scripts/check-lexicon-style.js

@@ -608,6 +608,18 @@ class StyleChecker {
 
     // Check if this is an external ref (e.g., "com.atproto.repo.strongRef" or "org.hypercerts.defs#uri")
     if (typeof ref === "string" && !ref.startsWith("#")) {
+      // Known-external lexicon namespaces are not present in the local lexicons/ directory.
+      // Skip resolution for these — they are valid by convention (the same namespaces skipped
+      // during file-level style checks).
+      const knownExternalPrefixes = [
+        "pub.leaflet.",
+        "app.bsky.",
+        "com.atproto.",
+      ];
+      if (knownExternalPrefixes.some((prefix) => ref.startsWith(prefix))) {
+        return;
+      }
+
       const resolvedDef = this.resolveExternalRef(ref);
       if (resolvedDef) {
         if (!resolvedDef.type) {

tests/validate-actor-organization.test.ts

@@ -35,7 +35,7 @@ describe("app.certified.actor.organization", () => {
     }
   });
 
-  it("should accept record with inline longDescription", () => {
+  it("should accept record with inline longDescription (descriptionString)", () => {
     const result = Organization.validateMain({
       $type: ids.AppCertifiedActorOrganization,
       longDescription: {