f173b975b7
Add Kosovo (XK) and Western Sahara (EH) to the country list. Kosovo has no Unicode emoji flag, so it follows the Tibet pattern with a bundled SVG asset that CountryFlag swaps in. Surface Tibet (CN-XZ) as a search-list entry so it can be picked from country autocompletes and pickers. The on-wire identifier stays iso3166:CN-XZ; only the picker pretends. Route every remaining raw country.flag span through CountryFlag so bundled SVGs render in autocomplete dropdowns, organizer selects, the ComposeBox destination switcher, and the world stats dialog.