feat(coding-agent): ResourceLoader, package management, and /reload command (#645)

- Add ResourceLoader interface and DefaultResourceLoader implementation
- Add PackageManager for npm/git extension sources with install/remove/update
- Add session.reload() and session.bindExtensions() APIs
- Add /reload command in interactive mode
- Add CLI flags: --skill, --theme, --prompt-template, --no-themes, --no-prompt-templates
- Add pi install/remove/update commands for extension management
- Refactor settings.json to use arrays for skills, prompts, themes
- Remove legacy SkillsSettings source flags and filters
- Update SDK examples and documentation for ResourceLoader pattern
- Add theme registration and loadThemeFromPath for dynamic themes
- Add getShellEnv to include bin dir in PATH for bash commands

packages/coding-agent/examples/sdk/09-api-keys-and-oauth.ts

@@ -4,19 +4,12 @@
  * Configure API key resolution via AuthStorage and ModelRegistry.
  */
 
-import {
-	AuthStorage,
-	createAgentSession,
-	discoverAuthStorage,
-	discoverModels,
-	ModelRegistry,
-	SessionManager,
-} from "@mariozechner/pi-coding-agent";
+import { AuthStorage, createAgentSession, ModelRegistry, SessionManager } from "@mariozechner/pi-coding-agent";
 
-// Default: discoverAuthStorage() uses ~/.pi/agent/auth.json
-// discoverModels() loads built-in + custom models from ~/.pi/agent/models.json
-const authStorage = discoverAuthStorage();
-const modelRegistry = discoverModels(authStorage);
+// Default: AuthStorage uses ~/.pi/agent/auth.json
+// ModelRegistry loads built-in + custom models from ~/.pi/agent/models.json
+const authStorage = new AuthStorage();
+const modelRegistry = new ModelRegistry(authStorage);
 
 await createAgentSession({
 	sessionManager: SessionManager.inMemory(),