fix: add clearer ripgrep install guidance

src/utils/ripgrep.test.ts

@@ -0,0 +1,27 @@
+import { expect, test } from 'bun:test'
+
+import { wrapRipgrepUnavailableError } from './ripgrep.ts'
+
+test('wrapRipgrepUnavailableError explains missing packaged fallback', () => {
+  const error = wrapRipgrepUnavailableError(
+    { code: 'ENOENT', message: 'spawn rg ENOENT' },
+    { mode: 'builtin', command: 'C:\\fake\\vendor\\ripgrep\\rg.exe' },
+    'win32',
+  )
+
+  expect(error.name).toBe('RipgrepUnavailableError')
+  expect(error.code).toBe('ENOENT')
+  expect(error.message).toContain('packaged ripgrep fallback')
+  expect(error.message).toContain('winget install BurntSushi.ripgrep.MSVC')
+})
+
+test('wrapRipgrepUnavailableError explains missing system ripgrep', () => {
+  const error = wrapRipgrepUnavailableError(
+    { code: 'ENOENT', message: 'spawn rg ENOENT' },
+    { mode: 'system', command: 'rg' },
+    'linux',
+  )
+
+  expect(error.message).toContain('system ripgrep binary was not found on PATH')
+  expect(error.message).toContain('apt install ripgrep')
+})