fix(read): image/pdf reads mark instructions as loaded without emitting system-reminder #33823

Description

Descripton

read on image/PDF sets metada.loaded but does not emit <system-reminder> with resolved instruction content.
This can cause instruction dedupe to skip later attachment of AGENTS.md even though the model never saw those instructions.

Plugins

None

OpenCode version

dev (local: 336d28f11)

Steps to reproduce

1. Add subdir/AGENTS.md with unique instruction.
2. In same session, ask opencode to invoke read on subdir/nested/image.png (or PDF).
3. Then run read on subdir/nested/index.ts.
4. Compare with skipping step 2.

Screenshot and/or share link

No response

Operating System

macOS 26 arm64

Terminal

iterm2