feat(web): open the local settings file

packages/settings/settings-local/src/index.ts

@@ -10,7 +10,7 @@
 import { Context, Service } from 'cordis'
 import z from 'schemastery'
 import { watch as chokidarWatch } from 'chokidar'
-import { mkdir, readFile } from 'node:fs/promises'
+import { mkdir, readFile, writeFile } from 'node:fs/promises'
 import { dirname, extname, join, resolve } from 'node:path'
 import { Document, parseDocument } from 'yaml'
 import { withFileLock, writeFileAtomic } from '@deepseek-ai/dsh-atomic-write'
@@ -96,6 +96,11 @@ function isENOENT(error: unknown): boolean {
   return (error as NodeJS.ErrnoException | null)?.code === 'ENOENT'
 }
 
+/** Whether an exclusive file create found an existing document. */
+function isEEXIST(error: unknown): boolean {
+  return (error as NodeJS.ErrnoException | null)?.code === 'EEXIST'
+}
+
 /** File-backed settings provider (`settings.yaml`/`.json`). */
 export class SettingsLocal extends Settings {
   static Config: z<Config> = z.object({
@@ -139,6 +144,29 @@ export class SettingsLocal extends Settings {
     return true
   }
 
+  /** The resolved YAML/JSON document path exposed to local configuration surfaces. */
+  override get documentPath(): string {
+    return this.spec.filename
+  }
+
+  /** Materialize an absent owner-only document, then return its resolved path. */
+  override prepareDocument(): Promise<string> {
+    return this.enqueue(async () => {
+      await mkdir(dirname(this.spec.filename), { recursive: true, mode: 0o700 })
+      await withFileLock(this.spec.filename, async () => {
+        try {
+          await writeFile(this.spec.filename, '', { flag: 'wx', mode: 0o600 })
+        } catch (error) {
+          if (isEEXIST(error)) return
+          throw error
+        }
+        this.text = ''
+        if (!this.isClosed()) this.publish({})
+      })
+      return this.spec.filename
+    })
+  }
+
   protected async load(): Promise<Record<string, unknown>> {
     let text: string
     try {