[AlexSchmidt1999]

What this PR does

English context and earlier messages can pull coach replies into English when NOOP runs in another language. Regular and streaming requests now append the running bundle's language to the system prompt, including morning briefs.

The saved custom prompt stays intact, and an explicit request for another language takes precedence. This changes the Apple integration only.

Type of change

• Bug fix

How it was tested

Prompt tests cover the supported language tags, an empty tag, and a custom prompt.

At 7b32548a4f40, the local macOS build and focused StrandTests passed. The iOS Release build, source hygiene, and diff-scoped Apple translation checks passed too. These are local results, separate from GitHub checks.

Checklist

• Generated projects, build output, and credentials are excluded.
• No new dependencies or destructive strap commands.

GitHub validation was rechecked on October 11 at 7b32548a4f40. All 5 registered checks passed, including the macOS app build and tests and the iOS app build.

[AlexSchmidt1999]

I am using NOOP 12.1.0 Release build 456 on my iPhone 17 Pro Max, and the app runs very smoothly in everyday use.

This PR is included in that combined build, together with my other Apple changes and the performance fixes from #2724 by @UtkuDenizAltiok and #2705 by @kavemang. The installed source is d67cceb5.

Both Apple builds and the local app, analytics, database and Python test suites passed for this combined build.