feat(terminal): add Nerd Font support for Powerline themes (#29)

web/package.json

@@ -21,6 +21,7 @@
         "@tanstack/react-query": "^5.90.12",
         "@tanstack/react-query-devtools": "^5.91.1",
         "@tanstack/react-router": "^1.143.6",
+        "@xterm/addon-canvas": "^0.7.0",
         "@xterm/addon-fit": "^0.11.0",
         "@xterm/addon-web-links": "^0.12.0",
         "@xterm/xterm": "^6.0.0",

web/src/components/Terminal/TerminalView.tsx

@@ -1,8 +1,10 @@
-import { useEffect, useRef } from 'react'
+import { useEffect, useRef, useState } from 'react'
 import { Terminal } from '@xterm/xterm'
 import { FitAddon } from '@xterm/addon-fit'
 import { WebLinksAddon } from '@xterm/addon-web-links'
+import { CanvasAddon } from '@xterm/addon-canvas'
 import '@xterm/xterm/css/xterm.css'
+import { createFontProvider, type ITerminalFontProvider } from '@/lib/terminalFont'
 
 function resolveThemeColors(): { background: string; foreground: string; selectionBackground: string } {
     const styles = getComputedStyle(document.documentElement)
@@ -20,6 +22,12 @@ export function TerminalView(props: {
     const containerRef = useRef<HTMLDivElement | null>(null)
     const onMountRef = useRef(props.onMount)
     const onResizeRef = useRef(props.onResize)
+    const [fontProvider, setFontProvider] = useState<ITerminalFontProvider | null>(null)
+
+    // Initialize font provider
+    useEffect(() => {
+        createFontProvider('default').then(setFontProvider)
+    }, [])
 
     useEffect(() => {
         onMountRef.current = props.onMount
@@ -31,14 +39,14 @@ export function TerminalView(props: {
 
     useEffect(() => {
         const container = containerRef.current
-        if (!container) {
+        if (!container || !fontProvider) {
             return
         }
 
         const { background, foreground, selectionBackground } = resolveThemeColors()
         const terminal = new Terminal({
             cursorBlink: true,
-            fontFamily: 'ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace',
+            fontFamily: fontProvider.getFontFamily(),
             fontSize: 13,
             theme: {
                 background,
@@ -46,13 +54,16 @@ export function TerminalView(props: {
                 cursor: foreground,
                 selectionBackground
             },
-            convertEol: true
+            convertEol: true,
+            customGlyphs: true
         })
 
         const fitAddon = new FitAddon()
         const webLinksAddon = new WebLinksAddon()
+        const canvasAddon = new CanvasAddon()
         terminal.loadAddon(fitAddon)
         terminal.loadAddon(webLinksAddon)
+        terminal.loadAddon(canvasAddon)
         terminal.open(container)
 
         const resizeTerminal = () => {
@@ -72,7 +83,7 @@ export function TerminalView(props: {
             observer.disconnect()
             terminal.dispose()
         }
-    }, [])
+    }, [fontProvider])
 
     return (
         <div

web/src/lib/terminalFont.ts

@@ -0,0 +1,81 @@
+/**
+ * Terminal Font Provider
+ *
+ * Provides font configuration for terminal rendering with Nerd Font support.
+ * Follows SOLID principles for easy extensibility.
+ */
+
+/**
+ * Terminal font provider interface
+ */
+export interface ITerminalFontProvider {
+    /**
+     * Get CSS fontFamily string for terminal
+     */
+    getFontFamily(): string
+
+    /**
+     * Optional async initialization (for future smart detection)
+     */
+    initialize?(): Promise<void>
+}
+
+/**
+ * Default font provider with hardcoded Nerd Font fallback list
+ * 
+ * Includes common Nerd Fonts and system fallbacks.
+ * Zero runtime overhead - uses browser's native font fallback mechanism.
+ */
+export class DefaultFontProvider implements ITerminalFontProvider {
+    private static readonly NERD_FONTS = [
+        // Common Nerd Fonts (prioritized by popularity)
+        'JetBrainsMono Nerd Font',
+        'JetBrainsMonoNerdFont',
+        'FiraCode Nerd Font',
+        'FiraCodeNerdFont',
+        'Hack Nerd Font',
+        'HackNerdFont',
+        'MapleMono NF',
+        'Maple Mono NF',
+        'Iosevka Nerd Font',
+        'IosevkaNerdFont',
+        'CaskaydiaCove Nerd Font',
+        'MesloLGS Nerd Font',
+        'SourceCodePro Nerd Font',
+        'UbuntuMono Nerd Font'
+    ]
+
+    private static readonly SYSTEM_FALLBACKS = [
+        'ui-monospace',
+        'SFMono-Regular',
+        'Menlo',
+        'Monaco',
+        'Consolas',
+        '"Liberation Mono"',
+        '"Courier New"',
+        'monospace'
+    ]
+
+    getFontFamily(): string {
+        return [
+            ...DefaultFontProvider.NERD_FONTS.map(f => `"${f}"`),
+            ...DefaultFontProvider.SYSTEM_FALLBACKS
+        ].join(', ')
+    }
+}
+
+/**
+ * Factory function to create font provider
+ * 
+ * @param mode - Provider mode (currently only 'default', extensible for future)
+ * @returns Font provider instance
+ */
+export async function createFontProvider(
+    mode: 'default' = 'default'
+): Promise<ITerminalFontProvider> {
+    switch (mode) {
+        case 'default':
+        default:
+            return new DefaultFontProvider()
+    }
+}