Three-column layout: photos · page · options rail

[ankitsejwal]

Reworks the editor into three columns, as sketched: left = photos, center = the page (centered), right = all options stacked vertically.

Layout

• Left: the dropzone + reorderable photo strip.
• Center: just the print sheet, centered, with the "Print sheet" heading above it. The selected-frame inspector now floats over the page (sticky bar) instead of sitting in a fixed row.
• Right: a new vertical OptionsPanel with two sections — Captions (location, date, font, camera info, captions) and Sheet (paper, per row, cut marks) — plus a full-width Export PDF. Sticky so it stays in view while you scroll.
• Collapses to a single stacked column (photos → page → options) below lg.

Cleanup
The horizontal toolbar components (SettingsToolbar, CaptionControls, CaptionFontControl, SheetControls) are replaced by OptionsPanel and removed.

On-frame editing is unchanged — drag to reposition + inline captions on the selected frame still work.

Verification (live)
Drove it via chrome-devtools against the dev server with 4 photos: confirmed the three columns, the centered page, the right rail's Captions/Sheet sections + Export, and that selecting a frame raises the floating inspector while the rail stays put. typecheck / oxlint / build green.