fix: TTS reading thinking content when reasoning has code blocks (#22237)

removeAllDetails() uses replaceOutsideCode() which splits content on
triple-backtick code blocks before applying the details-removal regex.

When thinking/reasoning content inside a <details> block contained
code blocks (backticks survive html.escape), the <details> opening
and </details> closing tags ended up in different split segments,
making the regex unable to match either. This caused thinking content
to leak through to TTS playback.

Fix: add a direct <details> strip (without code-block splitting) as
the first step of getMessageContentParts(), which is the TTS-specific
entry point. This catches the edge case while keeping removeAllDetails
safe for copy-to-clipboard (where legitimate <details> inside code
blocks should be preserved).

Fixes #22197

src/lib/utils/index.ts

@@ -956,6 +956,16 @@ export const extractSentencesForAudio = (text: string) => {
 };
 
 export const getMessageContentParts = (content: string, splitOn: string = 'punctuation') => {
+	// Strip <details> blocks directly on the full string before any
+	// code-block-aware processing. removeAllDetails (which callers use)
+	// applies the regex via replaceOutsideCode, which splits on triple-
+	// backtick code fences first. If a <details> block contains code
+	// fences (e.g. reasoning with code examples), the opening and
+	// closing tags land in separate segments and the regex fails,
+	// leaking thinking content into TTS. Applying the strip here on
+	// the full string catches those cases. (Fixes #22197)
+	content = content.replace(/<details[^>]*>[\s\S]*?<\/details>/gi, '');
+
 	const messageContentParts: string[] = [];
 
 	switch (splitOn) {