Add Risuai.readInlay(id) to plugin API v3

[ak45231-cyber]

Exposes the existing host-side getInlayAsset(id) (from src/ts/process/files/inlays.ts) to plugin sandboxes. Plugins can now read user-attached inlay images/audio/video by the UUID found in {{inlayed::}} placeholders inside raw message text.

Use case: custom-provider plugins that proxy chats to external endpoints need access to attached images to forward them in multi-modal API calls. The current plugin API exposes only sanitized text prompt_chat, leaving inlay binaries unreachable.

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Additional Notes

Footnotes

1. Modifies the behavior of prompting, requesting, or handling responses from AI models. ↩

2. Over 80% of the code is AI generated. ↩

[cubicj]

Verified the plugin API path. It exposes the existing inlay read path to v3 plugins without adding any inlay write or delete behavior.

Check, tests, and build pass locally.

Approving — thanks for the contribution!