feat(ui): nerd font icons on hard-defined list rows, graceful degrade

Tabs, Discover categories (replacing unused placeholder glyphs), Settings
sections, and the Feed 'Fetch More' row get Nerd Font glyphs (Font Awesome PUA
codepoints). When the terminal font isn't Nerd Font capable the glyphs render
nothing at all — no tofu, no layout gaps — via supportsNerdFonts() (env
allowlist + PODTUI_NERD_FONTS=1/0 override). Documented in README (Configuration
-> Fonts).

src/stores/discover.ts

@@ -20,17 +20,17 @@ export interface DiscoverCategory {
 }
 
 export const DISCOVER_CATEGORIES: DiscoverCategory[] = [
-	{ id: "all", name: "All", icon: "*" },
-	{ id: "technology", name: "Technology", icon: ">" },
-	{ id: "science", name: "Science", icon: "~" },
-	{ id: "comedy", name: "Comedy", icon: ")" },
-	{ id: "news", name: "News", icon: "!" },
-	{ id: "business", name: "Business", icon: "$" },
-	{ id: "health", name: "Health", icon: "+" },
-	{ id: "education", name: "Education", icon: "?" },
-	{ id: "sports", name: "Sports", icon: "#" },
-	{ id: "true-crime", name: "True Crime", icon: "%" },
-	{ id: "arts", name: "Arts", icon: "@" },
+	{ id: "all", name: "All", icon: "\uF0CA" },
+	{ id: "technology", name: "Technology", icon: "\uF2DB" },
+	{ id: "science", name: "Science", icon: "\uF0C3" },
+	{ id: "comedy", name: "Comedy", icon: "\uF118" },
+	{ id: "news", name: "News", icon: "\uF1EA" },
+	{ id: "business", name: "Business", icon: "\uF0B1" },
+	{ id: "health", name: "Health", icon: "\uF21E" },
+	{ id: "education", name: "Education", icon: "\uF19D" },
+	{ id: "sports", name: "Sports", icon: "\uF1E3" },
+	{ id: "true-crime", name: "True Crime", icon: "\uF00E" },
+	{ id: "arts", name: "Arts", icon: "\uF1FC" },
 ];
 
 // ── Remote featured-shows manifest ───────────────────────────────────────────