- Rewrite fitToCanvas to build the blurred story background with Imagick: scale the image to fill the width, heavily gaussian-blur it so shapes dissolve into a colour wash, gamma-lighten it, and mirror the top half onto the bottom for a symmetric background; the foreground is contained (fills the width, never cropped). Falls back to a GD downscale-blur on hosts without ext-imagick.
- Clean up the fit temp file if the blur/encode step throws.
- Update the editor preview (VerticalMediaCanvas) to a matching mirrored, lightened blur so it tracks the publish output.
- Cover the lightened image-derived background, the vertical mirror, and the GD fallback path with unit tests.
- Guard MediaOptimizer::fitToCanvas and cropToAspectRatio against huge-dimension sources (getimagesize budget check) so they fail cleanly instead of exhausting GD memory.
- Fit and crop now translate decode/process failures into a clean InstagramPublishException and remove their temp files via finally; the two paths are symmetric.
- publishStory reads the story canvas dimensions via data_get.
- Previews: restore the IG empty-state background, align the autoFitsImage suppression predicate to isImage, drop the explanatory comment, and use single-quote imports.
- Tests: real end-to-end story fit, undecodable/download/container failures, the memory guard (fit and crop), temp-file cleanup, blurred-background pixel assertions, and the aspect-ratio warning suppression.
Story images that aren't 9:16 were clipped by Instagram. They are now
fitted onto a 1080x1920 canvas — the image is contained and a blurred,
darkened copy of itself fills the letterbox gaps, so nothing is cropped
and the background color adapts to the image.
The fit happens at publish time (the hosted copy lives in social-crops/),
and the post editor preview now renders the same blurred-background fit
for stories, so the user sees exactly what will publish. The aspect-ratio
warning is suppressed for story images since they're auto-fitted.
Instagram only — Facebook stories are video-only in our flow.
