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/test/agent-session-concurrent.test.ts

@@ -13,6 +13,7 @@ import { AuthStorage } from "../src/core/auth-storage.js";
 import { ModelRegistry } from "../src/core/model-registry.js";
 import { SessionManager } from "../src/core/session-manager.js";
 import { SettingsManager } from "../src/core/settings-manager.js";
+import { createTestResourceLoader } from "./utilities.js";
 
 // Mock stream that mimics AssistantMessageEventStream
 class MockAssistantStream extends EventStream<AssistantMessageEvent, AssistantMessage> {
@@ -107,7 +108,9 @@ describe("AgentSession concurrent prompt guard", () => {
 			agent,
 			sessionManager,
 			settingsManager,
+			cwd: tempDir,
 			modelRegistry,
+			resourceLoader: createTestResourceLoader(),
 		});
 
 		return session;
@@ -197,7 +200,9 @@ describe("AgentSession concurrent prompt guard", () => {
 			agent,
 			sessionManager,
 			settingsManager,
+			cwd: tempDir,
 			modelRegistry,
+			resourceLoader: createTestResourceLoader(),
 		});
 
 		// First prompt completes