deleting uploaded media section (#185)

<!-- If this pull request closes an issue, please mention the issue
number below -->
Closes #164 

## 💸 TL;DR
<!-- What's the three sentence summary of purpose of the PR -->
Added a “Deleting uploaded media” section to the Media Uploads docs.

It clarifies that Devvit currently has no API to delete runtime assets
uploaded with media.upload(), distinguishes those from static media.dir
assets, and advises apps to remove stored references or update/delete
posts/comments that embed the media.

Author: vdikransamarjian

docs/capabilities/server/media-uploads.mdx

@@ -165,6 +165,18 @@ await reddit.submitComment({
 });
 ```
 
+## Deleting uploaded media
+
+Devvit does not currently provide an API to delete a media asset after it has been uploaded with `media.upload()`.
+
+This limitation applies to runtime Reddit-hosted uploads from `media.upload()`, not static assets bundled with your app through `media.dir` in `devvit.json`.
+
+The `mediaId` and `mediaUrl` returned by `media.upload()` identify a Reddit-hosted asset, but the current media API only supports upload. If your app needs to stop showing uploaded media, remove your app's references to the asset and update or delete the Reddit content that embeds it.
+
+For example:
+
+- If you store uploaded media in Redis, delete the Redis key or remove the item from your app's list of visible assets.
+- If the media is embedded in a post or comment, edit or delete that post or comment when your app has permission to do so.
 
 ## Canvas screenshots
 

versioned_docs/version-0.14/capabilities/server/media-uploads.mdx

@@ -165,6 +165,18 @@ await reddit.submitComment({
 });
 ```
 
+## Deleting uploaded media
+
+Devvit does not currently provide an API to delete a media asset after it has been uploaded with `media.upload()`.
+
+This limitation applies to runtime Reddit-hosted uploads from `media.upload()`, not static assets bundled with your app through `media.dir` in `devvit.json`.
+
+The `mediaId` and `mediaUrl` returned by `media.upload()` identify a Reddit-hosted asset, but the current media API only supports upload. If your app needs to stop showing uploaded media, remove your app's references to the asset and update or delete the Reddit content that embeds it.
+
+For example:
+
+- If you store uploaded media in Redis, delete the Redis key or remove the item from your app's list of visible assets.
+- If the media is embedded in a post or comment, edit or delete that post or comment when your app has permission to do so.
 
 ## Canvas screenshots