v0.3.0 Wave 13: projector CSS filter panel (invert, brightness, contrast, saturation, sepia, hue-rotate)

[900Labs]

Summary

Wave 13 adds a projector compensation filter panel to the presenter. Six CSS filters (invert, brightness, contrast, saturation, sepia, hue-rotate) apply to the audience window in real time, with debounced persistence to the deck.

What changed

Model (slides-core)

• ProjectorFilters struct (invert, brightness, contrast, saturation, sepia, hue_rotate) added to PresenterSettings with #[serde(default)]. Old decks default to neutral (no filtering).

Desktop (apps/desktop/)

• Filter toggle button in the presenter toolbar opens a popover with 6 slider/checkbox controls + a reset button.
• CSS filter: string applied to the audience window's slide container via style:filter. Only non-default properties included (e.g. brightness(1) omitted).
• Slider changes debounced into a single set_presenter_settings call.
• ProjectorFiltersDto added to the snapshot DTOs.

Test results

• 302 workspace tests pass.
• npm run check (svelte-check): 0 errors, 0 warnings.
• scripts/verify-local.sh: green. scripts/verify-public-release.sh: green.

What a reviewer should verify

1. Filter application — the CSS string only includes non-default properties.
2. Persistence — settings persist on the deck via SetPresenterSettings.
3. No XSS — no new @html in the filter panel code.

Remaining v0.3.0 items

• ODP import/export
• macOS .app release (CI/CD)