Regression in v2.1.124: input history up-arrow surfaces prompts from other projects

Summary

As of v2.1.124, pressing the up-arrow in the input box surfaces prompts from other projects and sessions, not just the current one. Previously this was scoped per-session/per-project.

Why this is bad

• Breaks the "fresh context per session" expectation
• Pollutes muscle-memory recall — I press up expecting this project's last prompt and get something from a completely unrelated repo
• The history picker (Ctrl+R) gained a Ctrl+S "narrow to project" toggle, but plain up-arrow has no equivalent escape hatch

Request

Either:

1. Revert up-arrow to per-project/per-session scope by default, OR
2. Add a settings.json option, e.g.:

{ "inputHistoryScope": "project" }

with values "global" | "project" | "session" (default "project").

Related

• #60791 (closed as duplicate without resolution)

Environment

• Claude Code v2.1.124+
• macOS