Refactor: collapse `OrbitPauseReasons` to a named-flag set / Set<PauseReason>

[khurchla]

Surfaced by the clarity-review pass on the v0.1.0 release branch (B1). Do NOT apply for v0.1.0 — captured for post-launch.

src/lib/scrambler/pause.ts:20-38 defines six independent booleans on OrbitPauseReasons and isOrbitPaused() ORs them. The shape is fine, but the call site in src/components/ScramblerCluster.svelte:124-133 (the $derived(isOrbitPaused({ ... })) block introduced by #43) has to rename every field at the boundary: hoverPaused → hover, focusPaused → focus, isDraggingCard → dragging. That rename layer is friction every time the file is read.

Two cleaner shapes worth considering:

1. Rename the local cluster $state variables to match the struct field-for-field (so the object literal collapses to shorthand: { hover, focus, tap, anyCardOpen, dragging, recentlyCollapsed }).
2. Change OrbitPauseReasons to a Set<PauseReason> (or a bitmask), so the cluster can pauseReasons.add('hover') / pauseReasons.delete('hover') directly without re-aliasing.

Either choice removes the rename layer and makes the contract single-sourced.

Files

• src/lib/scrambler/pause.ts
• src/components/ScramblerCluster.svelte
• tests/scrambler/orbit-pause.test.ts (test data shape updates accordingly)