refactor(core): rename attachments config to media (#39927)

Co-authored-by: Aiden Cline <rekram1-node@users.noreply.github.com>

packages/www/content/docs/(Configure)/attachments.mdx

@@ -111,7 +111,7 @@ Configure image normalization in `opencode.json` or `opencode.jsonc`:
 ```jsonc title="opencode.jsonc"
 {
   "$schema": "https://opencode.ai/config.json",
-  "attachments": {
+  "media": {
     "image": {
       "auto_resize": true,
       "max_width": 2000,

packages/www/content/docs/config.mdx

@@ -267,14 +267,14 @@ this field, but it does not start language servers yet.
 
 See the [LSP guide](/lsp) for accepted fields and current limitations.
 
-### Attachments
+### Media
 
 Control how oversized images loaded by the `read` tool are resized or rejected
 before they are sent to a model.
 
 ```jsonc
 {
-  "attachments": {
+  "media": {
     "image": {
       "auto_resize": true,
       "max_width": 2000,

packages/www/content/docs/migrate-v1.mdx

@@ -175,16 +175,16 @@ Rename the singular `snapshot` field to `snapshots`. Its boolean value does not
 { "snapshots": false }
 ```
 
-### Attachments
+### Media
 
-Rename the singular `attachment` object to `attachments`. Nested image settings keep the same names:
+Rename the singular `attachment` object to `media`. Nested image settings keep the same names:
 
 ```jsonc
 // V1
 { "attachment": { "image": { "auto_resize": true } } }
 
 // V2
-{ "attachments": { "image": { "auto_resize": true } } }
+{ "media": { "image": { "auto_resize": true } } }
 ```
 
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