feat: claude one-shot port from nanobot python codebase (v0.1.4.post4)

src/config/loader.ts

@@ -0,0 +1,65 @@
+import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'node:fs';
+import { homedir } from 'node:os';
+import { dirname, resolve } from 'node:path';
+import { type Config, ConfigSchema } from './types.ts';
+
+const DEFAULT_CONFIG_PATH = resolve(homedir(), '.nanobot', 'config.json');
+
+export function getConfigPath(override?: string): string {
+  return override ?? process.env['NANOBOT_CONFIG'] ?? DEFAULT_CONFIG_PATH;
+}
+
+export function loadConfig(configPath?: string): Config {
+  const path = getConfigPath(configPath);
+
+  if (!existsSync(path)) {
+    return ConfigSchema.parse({});
+  }
+
+  const raw = readFileSync(path, 'utf8');
+  let json: unknown;
+  try {
+    json = JSON.parse(raw);
+  } catch {
+    console.error(`Failed to parse config at ${path}`);
+    return ConfigSchema.parse({});
+  }
+
+  // Apply NANOBOT_ env var overrides before validation
+  const merged = applyEnvOverrides(json as Record<string, unknown>);
+  return ConfigSchema.parse(merged);
+}
+
+export function saveConfig(config: Config, configPath?: string): void {
+  const path = getConfigPath(configPath);
+  mkdirSync(dirname(path), { recursive: true });
+  writeFileSync(path, JSON.stringify(config, null, 2), 'utf8');
+}
+
+/** Resolve `~` in workspace path to the real home directory. */
+export function resolveWorkspacePath(raw: string): string {
+  if (raw.startsWith('~/') || raw === '~') {
+    return resolve(homedir(), raw.slice(2));
+  }
+  return resolve(raw);
+}
+
+function applyEnvOverrides(json: Record<string, unknown>): Record<string, unknown> {
+  const out = structuredClone(json);
+
+  const model = process.env['NANOBOT_MODEL'];
+  if (model) {
+    const agent = (out['agent'] as Record<string, unknown> | undefined) ?? {};
+    agent['model'] = model;
+    out['agent'] = agent;
+  }
+
+  const workspace = process.env['NANOBOT_WORKSPACE'];
+  if (workspace) {
+    const agent = (out['agent'] as Record<string, unknown> | undefined) ?? {};
+    agent['workspacePath'] = workspace;
+    out['agent'] = agent;
+  }
+
+  return out;
+}