feat(image): cross-platform clipboard paste, SVG support, and multi-model image handling

[im10furry]

Summary

Cross-platform image handling: clipboard paste on all platforms, SVG support, and multi-model image passthrough.

New Modules

src/utils/image/media.ts

• detectImageMediaType() - magic byte detection for PNG/JPEG/GIF/WebP
• normalizeSupportedImageMediaType() - MIME normalization (image/jpg to image/jpeg)
• isSvgBuffer() / isSvgExtension() - SVG detection
• rasterizeSvgToPng() - SVG to PNG via sharp
• imageBase64ToDataUrl() / imageBufferToDataUrl() - base64 to data: URL

src/utils/model/visionContent.ts

• extractTextAndImageUrls() - split text and images from mixed content arrays
• getImageUrlFromPart() - extract data: URLs from Anthropic, image_url, and input_image blocks
• toOpenAIImageUrlParts() / toResponsesImageParts() - format converters

Enhancements

Module	Change
FileReadTool	SVG support, detect media type from magic bytes not extension
imagePaste.ts	Windows (PowerShell) and Linux (wl-paste/xclip) support
ChatCompletions	Tool result images become adjacent user vision messages
ResponsesAPI	User images become input_image, tool result images become function_call_output
openaiMessageConversion	Tool result images become adjacent user vision messages
UI	ClipboardImage struct preserves actual media type

Tests (+13 cases)

Test file	Cases
image-media.test.ts	Magic byte detection, MIME normalization, data URL conversion
process-user-input-images.test.ts	Pasted image preserves JPEG media type
file-read-tool-parity.test.ts	SVG rasterization, JPEG/GIF/WebP content detection
chat-completions-e2e.test.ts	Tool result images to user vision message
responses-api-e2e.test.ts	User/tool images to input_image/function_call_output
openai-message-conversion.test.ts	Tool result images to user vision message

Gaps Closed

• Clipboard paste now works on Windows and Linux
• SVG files readable as images (rasterized to PNG)
• OpenAI Chat Completions and Responses API pass images through to model