Calg's WIM Skin

Added

• First release. Registers a WIM skin called Calg: flat dark panel chrome with a frost inner ring, a header bar carrying the class icon and class-coloured name, a body that is just the conversation, and a footer that is just the input box, its border lighting frost as you type.
• Header controls, right to left: close, settings (opens WIM's options) and history. No tooltips — the glyph is the label, as in the rest of these addons.
• Right-hand action rail built on WIM's ShortcutBar: Invite to Party, Ignore, and an Add to Calg's Portals / Enchanter / Summoner button for each of those addons that is installed, queueing the person you're whispering exactly as that addon's unit menu would. Invite to Guild is available but off. Which buttons appear is the SHOWN table at the top of Rail.lua; with it empty there is no rail and the chat display takes the full window width.
• Scroll arrows replaced by mouse-wheel scrolling plus the shared S.ScrollThumb hairline in the gutter.
• Tab strip restyled to match: recessed unselected tabs, a lifted tab with a gold title when selected, flat chevron pagers.
• Own emblem and rail glyphs, rendered by docs/icons/gen-icons.ps1.