fix(web): show full voice platform rules in settings preview (#1345)

Settings truncated read-only fixtures to 800 chars so scrolling never
revealed the rest. Default preview is now the full document; explicit
caps remain for tests.

Closes #1341

Co-authored-by: Cursor <cursoragent@cursor.com>

shared/src/voicePersonality.test.ts

@@ -11,7 +11,7 @@ import {
     truncateUtf8ByteLength,
     utf8ByteLength
 } from './voicePersonality'
-import { VOICE_PLATFORM_FIXTURES } from './voicePromptLayers'
+import { VOICE_PLATFORM_FIXTURES, getVoicePlatformFixturesPreview } from './voicePromptLayers'
 
 describe('voicePersonality', () => {
     test('parseVoicePersonalityPreferences returns defaults for invalid input', () => {
@@ -78,4 +78,10 @@ describe('voicePersonality', () => {
         const huge = truncateUtf8ByteLength('a'.repeat(50_000), 100)
         expect(utf8ByteLength(huge)).toBeLessThanOrEqual(100)
     })
+
+    test('settings fixtures preview returns full platform rules by default', () => {
+        expect(getVoicePlatformFixturesPreview()).toBe(VOICE_PLATFORM_FIXTURES)
+        expect(getVoicePlatformFixturesPreview(40)).toContain('[…]')
+        expect(getVoicePlatformFixturesPreview(40).length).toBeLessThan(VOICE_PLATFORM_FIXTURES.length)
+    })
 })

shared/src/voicePromptLayers.ts

@@ -205,9 +205,15 @@ export function composeVoiceAgentPrompt(
     return prompt
 }
 
-/** Short preview for Settings (fixtures are read-only). */
-export function getVoicePlatformFixturesPreview(maxChars = 600): string {
+/**
+ * Read-only fixtures text for Settings.
+ * Pass a finite maxChars only when deliberately truncating (e.g. tests);
+ * Settings shows the full document in a scrollable panel.
+ */
+export function getVoicePlatformFixturesPreview(maxChars?: number): string {
     const text = VOICE_PLATFORM_FIXTURES
-    if (text.length <= maxChars) return text
+    if (maxChars == null || !Number.isFinite(maxChars) || maxChars <= 0 || text.length <= maxChars) {
+        return text
+    }
     return `${text.slice(0, maxChars)}\n\n[…]`
 }