Keep the existing Inter and CJK export order and the UI font chain.
Defer Arabic export faces until joining and bidirectional ordering exist.
Restore main's headline documents and record remaining text-layout limits.
- Engine: slide_overlay (OverlaySettings in prefs.json, the new slideshow.overlays
command): identity plate (text, or a PNG/JPEG file with its transparency; size,
colour, opacity; render behind image), rating stars (own vector stars), up to 16
text overlays with tokens ({caption}, {exposure}, {file}, {date}, {focal}… plus
every rename token; unknown tags show as typed and are reported) and a drop
shadow, each at one of nine anchors of the slide or photo plus an offset, kept on
the slide; the export watermark on the photo. Sizes relative to the slide's
shorter side; validated and clamped.
- Drawn by the engine as a second pass over lightcraft_slideshow::compose_with
(new behind hook for "render behind image"); the watermark's text renderer moved
to engine text.rs (TextLayout, Inter + craft-fonts CJK) and is shared; glyphs
off the image are skipped so huge text stays cheap.
- rename::expand_tokens_with lets overlays add tokens without changing rename.
- Playback composes slides when overlays are on; slideshow.preview returns each
overlay's box. Settings > Slideshow > Overlays section with live preview.
- Docs: parity row (partial), whats-new, control/MCP docs, nine locale catalogs.
- Tests: tokens, nine anchors, star count, plate image opacity and missing file,
text shadow, resolution independence, hostile input, big-slide cost, CJK with
craft-fonts, prefs persistence, preview and headless playback pixel checks.