docs: update spectrum-ts documentation for v1.7.0 (#21)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: photon-action-bot[bot]

docs-src/spectrum-ts/custom-platforms.mdx.vel

@@ -96,6 +96,7 @@ export const myPlatform = definePlatform("my-platform", {
 | `space.resolve` | Yes | Resolves or creates a conversation. Receives an array of users plus optional params. |
 | `space.schema` | No | Optional Zod schema for the resolved space. |
 | `space.params` | No | Zod schema for additional space creation parameters — surfaces as the second arg to `platform(app).space()`. |
+| `space.actions` | No | A map of content-builder factories that become sugar methods on the resolved space. Each `space.<name>(...args)` delegates to `space.send(factory(...args))`. Names that collide with built-in `Space` methods (`send`, `edit`, `startTyping`, `stopTyping`, `responding`, `getMessage`) are skipped at runtime with a warning. |
 | `lifecycle.createClient` | Yes | Creates the platform client. Receives `config`, `projectId`, `projectSecret` (both may be `undefined`), and `store`. |
 | `lifecycle.destroyClient` | No | Tears down the client on shutdown. Omit if no cleanup is needed. |
 | `messages` | Yes | Async generator that yields incoming messages. |

docs-src/spectrum-ts/providers/imessage.mdx.vel

@@ -37,7 +37,7 @@ The iMessage provider supports three connection modes — local, cloud, and dedi
     ```
 
     <Note>
-      Local mode only supports sending text and attachments. Reactions, typing indicators, threaded replies, and group creation are not available.
+      Local mode only supports sending text and attachments. Reactions, typing indicators, threaded replies, group creation, and chat backgrounds are not available.
     </Note>
   </Tab>
   <Tab title="Dedicated">
@@ -170,6 +170,40 @@ The wrapped content can be a string or any `attachment(...)`. Effects only apply
   </Accordion>
 </AccordionGroup>
 
+## Chat backgrounds
+
+Set or clear the chat background image. Import `background` from the iMessage provider and use the sugar method on a narrowed space:
+
+```ts
+import { background, imessage } from "spectrum-ts/providers/imessage";
+
+const im = imessage(space);
+
+// Set from a file path — MIME type inferred from the extension
+await im.background("./wallpaper.jpg");
+
+// Set from a buffer — mimeType is required
+await im.background(buffer, { mimeType: "image/jpeg" });
+
+// Clear the current background
+await im.background("clear");
+```
+
+`space.background(...)` is sugar for `space.send(background(...))`. The canonical form works on any space reference:
+
+```ts
+await space.send(background("./wallpaper.jpg"));
+await space.send(background("clear"));
+```
+
+<Note>
+  Chat backgrounds require cloud or dedicated mode. In local mode, `background()` throws an `UnsupportedError`.
+</Note>
+
+<Note>
+  The string `"clear"` is a reserved sentinel. If you have a file literally named `clear` with no extension, pass `"./clear"` or load it as a `Buffer`.
+</Note>
+
 ## Tapback constants
 
 iMessage uses a fixed set of tapback reactions. The `imessage` object exposes them as constants: