Builds on the COD-37 registry: surfaces detected/registered attachments as
dismissible cards with a first-page thumbnail and an inline preview — the
consumer the registry PR deliberately deferred.
Backend:
- document-thumbnailer: first-page PNG thumbnails (PNG passthrough; PDF via
pdftoppm; Office via the preview cache).
- document-preview-cache: disk-cached DOCX/PPTX -> PDF conversion (LibreOffice
/ PowerShell COM), in-flight dedup, multi-converter fallback.
- file-routes: serveConvertedPreview / serveThumbnail + four routes —
GET .../attachments/:id/preview, .../thumbnail and the workspace-path
file-preview / file-thumbnail. Reuses the registry's TOCTOU-safe
resolveServableAttachmentPath, so previews stream the freshly-resolved path.
- server: enrich detected attachment events with a thumbnail route.
- image-watcher: .png now routes to attachment:detected — this PR adds the card
consumer, so the screenshot popup is no longer its only handler.
Frontend:
- panels-ui: attachment cards (addAttachmentCard, lazy stack, Clear-all,
per-session cleanup) plus a 3-arg openFilePreview that renders registered
attachments inline (image/PDF) or via the server-converted PDF (docx/pptx).
- app.js: wire attachment:detected -> _onAttachmentDetected and card state.
- styles: attachment-card + stack styling.
Verified: tsc / eslint / prettier / frontend-syntax clean; new thumbnailer +
preview-cache unit tests pass; full test:ci green (2861 passed); card render +
preview overlay + dismiss verified in-browser.
