⏯️ fix(tts): Resolve Voice Selection and Manual Playback Issues (#2845)

* fix: voice setting for autoplayback TTS

* fix(useTextToSpeechExternal): resolve stateful playback issues and consolidate state logic

* refactor: initialize tts voice and provider schema once per request

* fix(tts): edge case, longer text inputs. TODO: use continuous stream for longer text inputs

* fix(tts): pause global audio on conversation change

* refactor: keyvMongo ban cache to allow db updates for unbanning, to prevent server restart

* chore: eslint fix

* refactor: make ban cache exclusively keyvMongo

api/server/services/Files/Audio/streamAudio.spec.js

@@ -1,5 +1,5 @@
+const { createChunkProcessor, splitTextIntoChunks } = require('./streamAudio');
 const { Message } = require('~/models/Message');
-const { createChunkProcessor } = require('./streamAudio');
 
 jest.mock('~/models/Message', () => ({
   Message: {
@@ -86,3 +86,52 @@ describe('processChunks', () => {
     expect(Message.findOne().lean).toHaveBeenCalledTimes(2);
   });
 });
+
+describe('splitTextIntoChunks', () => {
+  test('splits text into chunks of specified size with default separators', () => {
+    const text = 'This is a test. This is only a test! Make sure it works properly? Okay.';
+    const chunkSize = 20;
+    const expectedChunks = [
+      { text: 'This is a test.', isFinished: false },
+      { text: 'This is only a test!', isFinished: false },
+      { text: 'Make sure it works p', isFinished: false },
+      { text: 'roperly? Okay.', isFinished: true },
+    ];
+
+    const result = splitTextIntoChunks(text, chunkSize);
+    expect(result).toEqual(expectedChunks);
+  });
+
+  test('splits text into chunks with default size', () => {
+    const text = 'A'.repeat(8000) + '. The end.';
+    const expectedChunks = [
+      { text: 'A'.repeat(4000), isFinished: false },
+      { text: 'A'.repeat(4000), isFinished: false },
+      { text: '. The end.', isFinished: true },
+    ];
+
+    const result = splitTextIntoChunks(text);
+    expect(result).toEqual(expectedChunks);
+  });
+
+  test('returns a single chunk if text length is less than chunk size', () => {
+    const text = 'Short text.';
+    const expectedChunks = [{ text: 'Short text.', isFinished: true }];
+
+    const result = splitTextIntoChunks(text, 4000);
+    expect(result).toEqual(expectedChunks);
+  });
+
+  test('handles text with no separators correctly', () => {
+    const text = 'ThisTextHasNoSeparatorsAndIsVeryLong'.repeat(100);
+    const chunkSize = 4000;
+    const expectedChunks = [{ text: text, isFinished: true }];
+
+    const result = splitTextIntoChunks(text, chunkSize);
+    expect(result).toEqual(expectedChunks);
+  });
+
+  test('throws an error when text is empty', () => {
+    expect(() => splitTextIntoChunks('')).toThrow('Text is required');
+  });
+});