Follow-Up to #45 & #46: Make Paste Bar navigation and handoff reliable

[alvst]

Summary

Fixes the rapid global-hotkey workflow: ⌘⇧V, Right Arrow, Return.

• Opens Pesty as a non-activating key panel, preserving the previous app’s focused control—for example, a selected Safari input—until paste returns to it.
• Handles the main-thread Carbon hotkey synchronously, so the bar is key and its local key monitor is installed before an immediately following Right Arrow arrives.
• Presents the Paste Bar at its final position immediately, without a slide-in animation or selection spring.
• Arrow-key selection no longer re-centers or right-anchors the whole strip when the next card is already visible; it scrolls only when the selected card is off-screen.
• Captures the actual non-Pesty destination when Return is pressed, orders the bar out synchronously, and sends ⌘V directly to that app’s process after the physical shortcut/Return keys lift. This removes the old global event/focus race and arbitrary handoff delay.
• Uses cooperative activation only for unusual menu-bar/reopen paths where the destination is not already active.
• ⌘C now always copies the primary selected Paste Bar item, rather than depending on a per-card SwiftUI key equivalent. A successful copy promotes its canonical clip to history item Add selected clip preview pane #1 with a fresh timestamp.
• Copy promotion intentionally does not reorder a pinboard or Paste Stack, whose ordering has separate semantics.
• Avoids an unnecessary full history JSON save when opening the bar does not prune any clips.
• Guards the deferred auto-hide path so an older resign-key event cannot close a newly re-keyed bar.

Relationship to preview work

#45 restores the detached, shadow-free preview above the selected card. This PR keeps the hotkey-to-selection and paste-handoff paths responsive while that preview remains open.

Dependency

Builds on #45 and #46 while those preview changes remain unmerged.

Validation

• swift build
• git diff --check

Screenshot

Debug Demo; Pesty window only.