feat(coding-agent): configurable app name and config dir for forks (#95)

- Add piConfig to package.json for app name and config directory
- Consolidate paths.ts into config.ts with clearer naming
- Fix Bun binary detection (changed from %7EBUN to $bunfs)
- Update all hardcoded paths to use config.ts exports
- getThemesDir() for built-in themes, getCustomThemesDir() for user themes

packages/coding-agent/src/oauth/storage.ts

@@ -1,6 +1,5 @@
 import { chmodSync, existsSync, mkdirSync, readFileSync, writeFileSync } from "fs";
-import { homedir } from "os";
-import { join } from "path";
+import { getAgentDir, getOAuthPath } from "../config.js";
 
 export interface OAuthCredentials {
 	type: "oauth";
@@ -13,19 +12,11 @@ interface OAuthStorageFormat {
 	[provider: string]: OAuthCredentials;
 }
 
-/**
- * Get path to oauth.json
- */
-function getOAuthFilePath(): string {
-	const configDir = join(homedir(), ".pi", "agent");
-	return join(configDir, "oauth.json");
-}
-
 /**
  * Ensure the config directory exists
  */
 function ensureConfigDir(): void {
-	const configDir = join(homedir(), ".pi", "agent");
+	const configDir = getAgentDir();
 	if (!existsSync(configDir)) {
 		mkdirSync(configDir, { recursive: true, mode: 0o700 });
 	}
@@ -35,7 +26,7 @@ function ensureConfigDir(): void {
  * Load all OAuth credentials from oauth.json
  */
 function loadStorage(): OAuthStorageFormat {
-	const filePath = getOAuthFilePath();
+	const filePath = getOAuthPath();
 	if (!existsSync(filePath)) {
 		return {};
 	}
@@ -54,7 +45,7 @@ function loadStorage(): OAuthStorageFormat {
  */
 function saveStorage(storage: OAuthStorageFormat): void {
 	ensureConfigDir();
-	const filePath = getOAuthFilePath();
+	const filePath = getOAuthPath();
 	writeFileSync(filePath, JSON.stringify(storage, null, 2), "utf-8");
 	// Set permissions to owner read/write only
 	chmodSync(filePath, 0o600);