fix: restore terminal config support and fix formatting

- Add GhosttyTerminalConfig struct and ghostty_terminal_new_with_config to WASM API
- Update GhosttyTerminal constructor to accept optional config parameter
- Update Ghostty.createTerminal() to pass config through
- Terminal class now passes theme/scrollback options to WASM config
- Add parseColor() helper to convert CSS colors to 0xRRGGBB format
- Fix double semicolon formatting issue in terminal.ts

Restored config options:
- scrollbackLimit: Max scrollback lines (0 = unlimited)
- fgColor: Default foreground color (0xRRGGBB)
- bgColor: Default background color (0xRRGGBB)
- cursorColor: Cursor color (0xRRGGBB)
- palette: 16-color ANSI palette

Author: sreya

lib/ghostty.ts

@@ -10,7 +10,9 @@ import {
   CellFlags,
   type Cursor,
   DirtyState,
+  GHOSTTY_CONFIG_SIZE,
   type GhosttyCell,
+  type GhosttyTerminalConfig,
   type GhosttyWasmExports,
   KeyEncoderOption,
   type KeyEvent,
@@ -27,6 +29,7 @@ export {
   type Cursor,
   DirtyState,
   type GhosttyCell,
+  type GhosttyTerminalConfig,
   KeyEncoderOption,
   type RGB,
   type RenderStateColors,
@@ -49,8 +52,12 @@ export class Ghostty {
     return new KeyEncoder(this.exports);
   }
 
-  createTerminal(cols: number = 80, rows: number = 24): GhosttyTerminal {
-    return new GhosttyTerminal(this.exports, this.memory, cols, rows);
+  createTerminal(
+    cols: number = 80,
+    rows: number = 24,
+    config?: GhosttyTerminalConfig
+  ): GhosttyTerminal {
+    return new GhosttyTerminal(this.exports, this.memory, cols, rows, config);
   }
 
   static async load(wasmPath?: string): Promise<Ghostty> {
@@ -261,13 +268,61 @@ export class GhosttyTerminal {
   /** Cell pool for zero-allocation rendering */
   private cellPool: GhosttyCell[] = [];
 
-  constructor(exports: GhosttyWasmExports, memory: WebAssembly.Memory, cols: number, rows: number) {
+  constructor(
+    exports: GhosttyWasmExports,
+    memory: WebAssembly.Memory,
+    cols: number = 80,
+    rows: number = 24,
+    config?: GhosttyTerminalConfig
+  ) {
     this.exports = exports;
     this.memory = memory;
     this._cols = cols;
     this._rows = rows;
 
-    this.handle = this.exports.ghostty_terminal_new(cols, rows);
+    if (config) {
+      // Allocate config struct in WASM memory
+      const configPtr = this.exports.ghostty_wasm_alloc_u8_array(GHOSTTY_CONFIG_SIZE);
+      if (configPtr === 0) {
+        throw new Error('Failed to allocate config (out of memory)');
+      }
+
+      try {
+        // Write config to WASM memory
+        const view = new DataView(this.memory.buffer);
+        let offset = configPtr;
+
+        // scrollback_limit (u32)
+        view.setUint32(offset, config.scrollbackLimit ?? 10000, true);
+        offset += 4;
+
+        // fg_color (u32)
+        view.setUint32(offset, config.fgColor ?? 0, true);
+        offset += 4;
+
+        // bg_color (u32)
+        view.setUint32(offset, config.bgColor ?? 0, true);
+        offset += 4;
+
+        // cursor_color (u32)
+        view.setUint32(offset, config.cursorColor ?? 0, true);
+        offset += 4;
+
+        // palette[16] (u32 * 16)
+        for (let i = 0; i < 16; i++) {
+          view.setUint32(offset, config.palette?.[i] ?? 0, true);
+          offset += 4;
+        }
+
+        this.handle = this.exports.ghostty_terminal_new_with_config(cols, rows, configPtr);
+      } finally {
+        // Free the config memory
+        this.exports.ghostty_wasm_free_u8_array(configPtr, GHOSTTY_CONFIG_SIZE);
+      }
+    } else {
+      this.handle = this.exports.ghostty_terminal_new(cols, rows);
+    }
+
     if (!this.handle) throw new Error('Failed to create terminal');
 
     this.initCellPool();

lib/terminal.ts

@@ -17,7 +17,7 @@
 
 import { BufferNamespace } from './buffer';
 import { EventEmitter } from './event-emitter';
-import type { Ghostty, GhosttyCell, GhosttyTerminal } from './ghostty';
+import type { Ghostty, GhosttyCell, GhosttyTerminal, GhosttyTerminalConfig } from './ghostty';
 import { getGhostty } from './index';
 import { InputHandler } from './input-handler';
 import type {
@@ -38,6 +38,101 @@ import { CanvasRenderer } from './renderer';
 import { SelectionManager } from './selection-manager';
 import type { ILink, ILinkProvider } from './types';
 
+// ============================================================================
+// Helpers
+// ============================================================================
+
+/**
+ * Parse a CSS color string to 0xRRGGBB format.
+ * Supports hex (#RGB, #RRGGBB), rgb(), and named colors.
+ */
+function parseColor(color: string | undefined): number {
+  if (!color) return 0;
+
+  // Handle hex colors
+  if (color.startsWith('#')) {
+    const hex = color.slice(1);
+    if (hex.length === 3) {
+      // #RGB -> #RRGGBB
+      const r = Number.parseInt(hex[0] + hex[0], 16);
+      const g = Number.parseInt(hex[1] + hex[1], 16);
+      const b = Number.parseInt(hex[2] + hex[2], 16);
+      return (r << 16) | (g << 8) | b;
+    } else if (hex.length === 6) {
+      return Number.parseInt(hex, 16);
+    }
+  }
+
+  // Handle rgb(r, g, b)
+  const rgbMatch = color.match(/rgb\s*\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)/i);
+  if (rgbMatch) {
+    const r = Number.parseInt(rgbMatch[1], 10);
+    const g = Number.parseInt(rgbMatch[2], 10);
+    const b = Number.parseInt(rgbMatch[3], 10);
+    return (r << 16) | (g << 8) | b;
+  }
+
+  // For named colors, return 0 (use default)
+  return 0;
+}
+
+/**
+ * Build GhosttyTerminalConfig from ITerminalOptions
+ */
+function buildTerminalConfig(options: ITerminalOptions): GhosttyTerminalConfig | undefined {
+  const theme = options.theme;
+  const scrollback = options.scrollback;
+
+  // If no customizations, return undefined to use defaults
+  if (!theme && scrollback === undefined) {
+    return undefined;
+  }
+
+  const config: GhosttyTerminalConfig = {};
+
+  if (scrollback !== undefined) {
+    config.scrollbackLimit = scrollback;
+  }
+
+  if (theme) {
+    config.fgColor = parseColor(theme.foreground);
+    config.bgColor = parseColor(theme.background);
+    config.cursorColor = parseColor(theme.cursor);
+
+    // Build palette from theme colors
+    const palette: number[] = [];
+    const paletteColors = [
+      theme.black,
+      theme.red,
+      theme.green,
+      theme.yellow,
+      theme.blue,
+      theme.magenta,
+      theme.cyan,
+      theme.white,
+      theme.brightBlack,
+      theme.brightRed,
+      theme.brightGreen,
+      theme.brightYellow,
+      theme.brightBlue,
+      theme.brightMagenta,
+      theme.brightCyan,
+      theme.brightWhite,
+    ];
+
+    for (const color of paletteColors) {
+      palette.push(parseColor(color));
+    }
+
+    // Only set palette if at least one color is defined
+    if (palette.some((c) => c !== 0)) {
+      config.palette = palette;
+    }
+  }
+
+  return config;
+}
+
 // ============================================================================
 // Terminal Class
 // ============================================================================
@@ -259,8 +354,9 @@ export class Terminal implements ITerminalCore {
       parent.setAttribute('aria-label', 'Terminal input');
       parent.setAttribute('aria-multiline', 'true');
 
-      // Create WASM terminal with current dimensions
-      this.wasmTerm = this.ghostty!.createTerminal(this.cols, this.rows);;
+      // Create WASM terminal with current dimensions and config
+      const config = buildTerminalConfig(this.options);
+      this.wasmTerm = this.ghostty!.createTerminal(this.cols, this.rows, config);
 
       // Create canvas element
       this.canvas = document.createElement('canvas');
@@ -560,7 +656,8 @@ export class Terminal implements ITerminalCore {
     if (this.wasmTerm) {
       this.wasmTerm.free();
     }
-    this.wasmTerm = this.ghostty!.createTerminal(this.cols, this.rows);
+    const config = buildTerminalConfig(this.options);
+    this.wasmTerm = this.ghostty!.createTerminal(this.cols, this.rows, config);
 
     // Clear renderer
     this.renderer!.clear();

lib/types.ts

@@ -344,6 +344,7 @@ export interface GhosttyWasmExports extends WebAssembly.Exports {
 
   // Terminal lifecycle
   ghostty_terminal_new(cols: number, rows: number): TerminalHandle;
+  ghostty_terminal_new_with_config(cols: number, rows: number, configPtr: number): TerminalHandle;
   ghostty_terminal_free(terminal: TerminalHandle): void;
   ghostty_terminal_resize(terminal: TerminalHandle, cols: number, rows: number): void;
   ghostty_terminal_write(terminal: TerminalHandle, dataPtr: number, dataLen: number): void;
@@ -427,14 +428,23 @@ export const CURSOR_STRUCT_SIZE = 8;
  */
 export const COLORS_STRUCT_SIZE = 12;
 
-// Legacy - kept for compatibility but not used with new API
+/**
+ * Terminal configuration (passed to ghostty_terminal_new_with_config)
+ * All color values use 0xRRGGBB format. A value of 0 means "use default".
+ */
 export interface GhosttyTerminalConfig {
   scrollbackLimit?: number;
   fgColor?: number;
   bgColor?: number;
   cursorColor?: number;
   palette?: number[];
 }
+
+/**
+ * Size of GhosttyTerminalConfig struct in WASM memory (bytes).
+ * Layout: scrollback_limit(u32) + fg_color(u32) + bg_color(u32) + cursor_color(u32) + palette[16](u32*16)
+ * Total: 4 + 4 + 4 + 4 + 64 = 80 bytes
+ */
 export const GHOSTTY_CONFIG_SIZE = 80;
 
 /**