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/components/TabPanel.tsx

@@ -20,6 +20,7 @@ import { useTheme } from "@/context/ThemeContext";
 import { useNavigation } from "@/context/NavigationContext";
 import { useScrollIntoView } from "@/hooks/useScrollIntoView";
 import { TABS } from "@/utils/navigation";
+import { NF_ICONS, supportsNerdFonts } from "@/utils/nerd-fonts";
 
 const TAB_LABEL: Record<TABS, string> = {
 	[TABS.FEED]: "Feed",
@@ -30,12 +31,24 @@ const TAB_LABEL: Record<TABS, string> = {
 	[TABS.SETTINGS]: "Settings",
 };
 
+/** Nerd Font glyph per tab (rendered only when the terminal supports them). */
+const TAB_ICON: Record<TABS, string> = {
+	[TABS.FEED]: NF_ICONS.feed,
+	[TABS.MYSHOWS]: NF_ICONS.shows,
+	[TABS.DISCOVER]: NF_ICONS.discover,
+	[TABS.SEARCH]: NF_ICONS.search,
+	[TABS.PLAYER]: NF_ICONS.player,
+	[TABS.SETTINGS]: NF_ICONS.settings,
+};
+
 /** Numeric TABS values, in declaration order (1..TabsCount). */
 const TAB_ORDER = Object.values(TABS).filter(
 	(v): v is TABS => typeof v === "number",
 ) as TABS[];
 
 export function TabListPane(props: { muted?: boolean }) {
+	// Static: detection never changes mid-session.
+	const nerd = supportsNerdFonts();
 	const { theme } = useTheme();
 	const nav = useNavigation();
 
@@ -92,6 +105,11 @@ export function TabListPane(props: { muted?: boolean }) {
 					>
 						{/* ── selection marker (j/k cursor) ─────────────────────────── */}
 						<text fg={focusFg(tab)}>{isCursor() ? "❯" : " "}</text>
+						{nerd && (
+							<text fg={focusFg(tab)} paddingRight={1}>
+								{TAB_ICON[tab]}
+							</text>
+						)}
 						<text fg={isCursor() ? focusFg(tab) : theme.textMuted}>{tab}</text>
 						<text fg={labelFg()} paddingLeft={1}>
 							{TAB_LABEL[tab]}