feat: standalone binary support with Bun

- Add build:binary script for Bun compilation
- Add paths.ts for cross-platform asset resolution (npm/bun/tsx)
- Add GitHub Actions workflow for automated binary releases
- Update README with installation options

Based on #89 by @steipete

packages/coding-agent/src/changelog.ts

@@ -1,6 +1,4 @@
 import { existsSync, readFileSync } from "fs";
-import { dirname, join } from "path";
-import { fileURLToPath } from "url";
 
 export interface ChangelogEntry {
 	major: number;
@@ -97,11 +95,5 @@ export function getNewEntries(entries: ChangelogEntry[], lastVersion: string): C
 	return entries.filter((entry) => compareVersions(entry, last) > 0);
 }
 
-/**
- * Get the path to the CHANGELOG.md file
- */
-export function getChangelogPath(): string {
-	const __filename = fileURLToPath(import.meta.url);
-	const __dirname = dirname(__filename);
-	return join(__dirname, "../CHANGELOG.md");
-}
+// Re-export getChangelogPath from paths.ts for convenience
+export { getChangelogPath } from "./paths.js";

packages/coding-agent/src/export-html.ts

@@ -2,14 +2,12 @@ import type { AgentState } from "@mariozechner/pi-agent-core";
 import type { AssistantMessage, Message, ToolResultMessage, UserMessage } from "@mariozechner/pi-ai";
 import { existsSync, readFileSync, writeFileSync } from "fs";
 import { homedir } from "os";
-import { basename, dirname, join } from "path";
-import { fileURLToPath } from "url";
+import { basename } from "path";
+import { getPackageJsonPath } from "./paths.js";
 import type { SessionManager } from "./session-manager.js";
 
 // Get version from package.json
-const __filename = fileURLToPath(import.meta.url);
-const __dirname = dirname(__filename);
-const packageJson = JSON.parse(readFileSync(join(__dirname, "../package.json"), "utf-8"));
+const packageJson = JSON.parse(readFileSync(getPackageJsonPath(), "utf-8"));
 const VERSION = packageJson.version;
 
 /**

packages/coding-agent/src/main.ts

@@ -4,11 +4,11 @@ import { ProcessTerminal, TUI } from "@mariozechner/pi-tui";
 import chalk from "chalk";
 import { existsSync, readFileSync, statSync } from "fs";
 import { homedir } from "os";
-import { dirname, extname, join, resolve } from "path";
-import { fileURLToPath } from "url";
+import { extname, join, resolve } from "path";
 import { getChangelogPath, getNewEntries, parseChangelog } from "./changelog.js";
 import { exportFromFile } from "./export-html.js";
 import { findModel, getApiKeyForModel, getAvailableModels } from "./model-config.js";
+import { getPackageJsonPath, getReadmePath } from "./paths.js";
 import { SessionManager } from "./session-manager.js";
 import { SettingsManager } from "./settings-manager.js";
 import { expandSlashCommand, loadSlashCommands } from "./slash-commands.js";
@@ -19,9 +19,7 @@ import { SessionSelectorComponent } from "./tui/session-selector.js";
 import { TuiRenderer } from "./tui/tui-renderer.js";
 
 // Get version from package.json
-const __filename = fileURLToPath(import.meta.url);
-const __dirname = dirname(__filename);
-const packageJson = JSON.parse(readFileSync(join(__dirname, "../package.json"), "utf-8"));
+const packageJson = JSON.parse(readFileSync(getPackageJsonPath(), "utf-8"));
 const VERSION = packageJson.version;
 
 const defaultModelPerProvider: Record<KnownProvider, string> = {
@@ -374,7 +372,7 @@ function buildSystemPrompt(customPrompt?: string, selectedTools?: ToolName[]): s
 	});
 
 	// Get absolute path to README.md
-	const readmePath = resolve(join(__dirname, "../README.md"));
+	const readmePath = getReadmePath();
 
 	// Build tools list based on selected tools
 	const tools = selectedTools || (["read", "bash", "edit", "write"] as ToolName[]);

packages/coding-agent/src/paths.ts

@@ -0,0 +1,66 @@
+import { existsSync } from "fs";
+import { dirname, join, resolve } from "path";
+import { fileURLToPath } from "url";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+/**
+ * Detect if we're running as a Bun compiled binary.
+ * Bun binaries have import.meta.url starting with "file:///$bunfs/"
+ */
+export const isBunBinary = import.meta.url.startsWith("file:///$bunfs/");
+
+/**
+ * Get the base directory for resolving package assets (themes, package.json, README.md, CHANGELOG.md).
+ * - For Bun binary: returns the directory containing the executable
+ * - For Node.js (dist/): returns __dirname (the dist/ directory)
+ * - For tsx (src/): returns parent directory (the package root)
+ */
+export function getPackageDir(): string {
+	if (isBunBinary) {
+		// Bun binary: resolve relative to the executable
+		return dirname(process.execPath);
+	}
+	// Node.js: check if package.json exists in __dirname (dist/) or parent (src/ case)
+	if (existsSync(join(__dirname, "package.json"))) {
+		return __dirname;
+	}
+	// Running from src/ via tsx - go up one level to package root
+	return dirname(__dirname);
+}
+
+/**
+ * Get path to the theme directory
+ * - For Bun binary: dist/theme/ next to executable
+ * - For Node.js (dist/): dist/theme/
+ * - For tsx (src/): src/theme/
+ */
+export function getThemeDir(): string {
+	if (isBunBinary) {
+		return join(dirname(process.execPath), "theme");
+	}
+	// __dirname is either dist/ or src/ - theme is always a subdirectory
+	return join(__dirname, "theme");
+}
+
+/**
+ * Get path to package.json
+ */
+export function getPackageJsonPath(): string {
+	return join(getPackageDir(), "package.json");
+}
+
+/**
+ * Get path to README.md
+ */
+export function getReadmePath(): string {
+	return resolve(join(getPackageDir(), "README.md"));
+}
+
+/**
+ * Get path to CHANGELOG.md
+ */
+export function getChangelogPath(): string {
+	return resolve(join(getPackageDir(), "CHANGELOG.md"));
+}

packages/coding-agent/src/theme/theme.ts

@@ -1,13 +1,11 @@
 import * as fs from "node:fs";
 import * as os from "node:os";
 import * as path from "node:path";
-import { fileURLToPath } from "node:url";
 import type { EditorTheme, MarkdownTheme, SelectListTheme } from "@mariozechner/pi-tui";
 import { type Static, Type } from "@sinclair/typebox";
 import { TypeCompiler } from "@sinclair/typebox/compiler";
 import chalk from "chalk";
-
-const __dirname = path.dirname(fileURLToPath(import.meta.url));
+import { getThemeDir } from "../paths.js";
 
 // ============================================================================
 // Types & Schema
@@ -321,8 +319,9 @@ let BUILTIN_THEMES: Record<string, ThemeJson> | undefined;
 
 function getBuiltinThemes(): Record<string, ThemeJson> {
 	if (!BUILTIN_THEMES) {
-		const darkPath = path.join(__dirname, "dark.json");
-		const lightPath = path.join(__dirname, "light.json");
+		const themeDir = getThemeDir();
+		const darkPath = path.join(themeDir, "dark.json");
+		const lightPath = path.join(themeDir, "light.json");
 		BUILTIN_THEMES = {
 			dark: JSON.parse(fs.readFileSync(darkPath, "utf-8")) as ThemeJson,
 			light: JSON.parse(fs.readFileSync(lightPath, "utf-8")) as ThemeJson,