Desktop app 0.12.5 — An ordinary maths question could take the app down

A desktop-only release — the engine stays at 0.12.4, which this build bundles. Two of these shipped in front of every new user: a reply containing a formula quit the app outright, and the starter model everyone landed on fell apart on the kind of question people try first.

• Maths no longer crashes the app. When a reply contained a formula the app quit with a macOS crash dialog, and a plain 2 + 2 = 4 was enough to trigger it. Formulas now render as their plain-text source rather than taking the app down; proper typesetting is still to come.
• The starter model was unusable and has been replaced. The pick that shipped with 0.12.1 came apart on ordinary multi-step questions — doubling words together, then looping until it ran out of room. Measured on the same Mac against the same question: 0/4 correct before, 16/16 after, with the first answer arriving in about a second. Anyone still on the retired starter is walked back through first-run setup rather than left on it (PR #1484).
• A silent server no longer hangs the chat. Sending a message used to sit there indefinitely if the model stopped responding. It now fails after a bounded wait and the message stays retryable.
• Loading a model that will not fit is blocked instead of freezing the Mac. The check reads free memory at that moment and warns, rather than letting the load proceed into a freeze or a kernel panic.
• Your API key is no longer shown in the clear in the copyable setup snippets on the Launch page.
• Cursor no longer gets a configuration that cannot work. Cursor routes requests through its own servers, so a localhost address was never reachable from it. The app now says so and points at Claude Code, Cline, or Continue for a genuinely local connection.
• Two models that could fail to answer are hidden for now. Ministral 3 and Gemma 4 E2B looked like ordinary small chat models in the picker, but on some Macs they returned no reply at all. They stay hidden until that is fixed.
• Quitting no longer stalls or crashes, and launching the app no longer risks shutting down a rapid-mlx serve you started yourself in a terminal. Conversation history keeps its order, the compose box grows with what you type, and the transcript stops yanking you to the bottom while you read further up.