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/src/core/model-registry.ts

@@ -15,6 +15,8 @@ import { type Static, Type } from "@sinclair/typebox";
 import AjvModule from "ajv";
 import { execSync } from "child_process";
 import { existsSync, readFileSync } from "fs";
+import { join } from "path";
+import { getAgentDir } from "../config.js";
 import type { AuthStorage } from "./auth-storage.js";
 
 const Ajv = (AjvModule as any).default || AjvModule;
@@ -159,7 +161,7 @@ export class ModelRegistry {
 
 	constructor(
 		readonly authStorage: AuthStorage,
-		private modelsJsonPath: string | undefined = undefined,
+		private modelsJsonPath: string | undefined = join(getAgentDir(), "models.json"),
 	) {
 		// Set up fallback resolver for custom provider API keys
 		this.authStorage.setFallbackResolver((provider) => {