feat(hooks): add read-image-resizer hook

Intercepts Read tool output with image attachments and resizes to comply with Anthropic API limits (≤1568px long edge, ≤5MB). Only activates for Anthropic provider sessions and appends resize metadata (original/new resolution, token count) to tool output.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/config/schema/hooks.ts

@@ -49,6 +49,7 @@ export const HookNameSchema = z.enum([
   "write-existing-file-guard",
   "anthropic-effort",
   "hashline-read-enhancer",
+  "read-image-resizer",
 ])
 
 export type HookName = z.infer<typeof HookNameSchema>