Add full clip context menu actions

[alvst]

What changed

• Adds a native right-click menu for clip cards with SF Symbol icons and macOS-style separators/shortcuts.
• Adds dynamic Paste to , Paste as Plain Text, Copy, Rename, Delete, Preview, and Share actions.
• Adds a colored Pin submenu and Create Pinboard….
• Adds real clip-payload editing for text, rich text, links, and colors; edits update matching history and pinboard copies and refresh the clipboard without creating a duplicate history entry.
• Shows native Writing Tools only for eligible text clips when macOS 15.2+ reports it is available.

Why

This implements the complete contextual workflow requested for a clip, including the system-provided Writing Tools path rather than an imitation.

Validation

• swift build
• VERSION=1.0.0 BUILD=1 ./scripts/build_app.sh
• git diff --check
• Demo-mode UI verification of the menu, Edit dialog, Preview, dynamic paste target, and Writing Tools availability gating.

Screenshots

Demo mode — Pesty window only.