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/export-html.ts

@@ -3,13 +3,9 @@ import type { AssistantMessage, Message, ToolResultMessage, UserMessage } from "
 import { existsSync, readFileSync, writeFileSync } from "fs";
 import { homedir } from "os";
 import { basename } from "path";
-import { getPackageJsonPath } from "./paths.js";
+import { VERSION } from "./config.js";
 import type { SessionManager } from "./session-manager.js";
 
-// Get version from package.json
-const packageJson = JSON.parse(readFileSync(getPackageJsonPath(), "utf-8"));
-const VERSION = packageJson.version;
-
 /**
  * TUI Color scheme (matching exact RGB values from TUI components)
  */