fix(tui): use platform-specific config path in login prompt

packages/zcode-tui/src/index.ts

@@ -1,7 +1,7 @@
 import { spawn } from "node:child_process";
 import { appendFileSync } from "node:fs";
 
-import { readConfiguredModelAccess } from "../../../src/model-access.ts";
+import { readConfiguredModelAccess, userConfigPathHint } from "../../../src/model-access.ts";
 import {
   availableUpdateVersion,
   readStartupUpdate,
@@ -664,12 +664,13 @@ class ZCodeTui {
   }
 
   private updateLoginWarning(): void {
+    const configPath = userConfigPathHint();
     this.loginWarning.setText(
       this.loginRequired ? this.theme.warning("Model access is not configured.") : ""
     );
     this.loginHelp.setText(
       this.loginRequired
-        ? this.theme.warning("Run /login, or configure a custom provider in ~/.zcode/cli/config.json.")
+        ? this.theme.warning(`Run /login, or configure a custom provider in ${configPath}.`)
         : ""
     );
   }
@@ -2798,8 +2799,9 @@ class ZCodeTui {
       const command = selected?.payload as SelectionCommand | undefined;
       if (!command?.command) return;
       if (command.command === customProviderHelpCommand) {
+        const configPath = userConfigPathHint();
         this.addNotice(
-          "Custom providers do not require login. Copy config.example.json to ~/.zcode/cli/config.json, "
+          `Custom providers do not require login. Copy config.example.json to ${configPath}, `
           + "set provider kind, baseURL, apiKey and model IDs, then run /new. "
           + "See README: Custom provider without login.",
           "muted"

src/model-access.ts

@@ -61,6 +61,12 @@ export function userConfigPath(
   return path.join(configuredHome || fallbackHome, ".zcode", "cli", "config.json");
 }
 
+export function userConfigPathHint(platform: NodeJS.Platform = process.platform): string {
+  return platform === "win32"
+    ? "%USERPROFILE%\\.zcode\\cli\\config.json"
+    : "~/.zcode/cli/config.json";
+}
+
 export async function ensureUserConfig(
   env: NodeJS.ProcessEnv = process.env
 ): Promise<UserConfigBootstrapResult> {

test/model-access.test.ts

@@ -3,7 +3,7 @@ import { mkdtemp, mkdir, rm, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 
-import { readConfiguredModelAccess, userConfigPath } from "../src/model-access.ts";
+import { readConfiguredModelAccess, userConfigPath, userConfigPathHint } from "../src/model-access.ts";
 
 const temporaryDirectories: string[] = [];
 
@@ -20,6 +20,12 @@ async function temporaryHome(): Promise<string> {
 }
 
 describe("configured model access", () => {
+  test("formats the config path hint for each supported platform", () => {
+    expect(userConfigPathHint("linux")).toBe("~/.zcode/cli/config.json");
+    expect(userConfigPathHint("darwin")).toBe("~/.zcode/cli/config.json");
+    expect(userConfigPathHint("win32")).toBe("%USERPROFILE%\\.zcode\\cli\\config.json");
+  });
+
   test("detects an internally consistent custom provider", async () => {
     const home = await temporaryHome();
     const env = { HOME: home, USERPROFILE: home };