[ashmitvoid]

Summary

• add bounded image metadata/EXIF probing through the existing no-follow preview helper
• keep static image rendering on the bounded thumbnail pipeline and add 1×–4× fit/zoom/pan controls
• add explicit GIF/WebP Quick Look on the existing ExplicitLongWork scheduler lane; no passive autoplay
• stop animation on selection/path changes, preview deactivation, explicit Stop, or reduced-motion activation
• bound metadata input, animation input, dimensions, frame count, frame delay, encoded frames, and total play duration
• add image-preview tests plus Arch/CI dependencies and linkage validation for Exiv2 and Qt image formats
• validate common EXIF fields with a standards-correct JPEG fixture containing a real EXIF sub-IFD

Security / performance invariants

• Exiv2 receives bounded bytes copied from an already-secured O_NOFOLLOW descriptor, never the pathname
• explicit animation copies at most 64 MiB into helper memory and releases the selected-file descriptor before frame playback
• static zoom does not trigger full-resolution source decoding; it scales the existing bounded thumbnail surface
• no second preview service, recursive scans, passive decoder loop, or hidden animation timer

Validation target

Frozen head: 3021367c1894aec84d01f81df4e5d44a8870cef4

Closes #85