v0.12.1

Fixed

• Windows: prompt = ... stderr line used backslash separators.
  formatPromptSource now normalises its output to forward slashes
  so the user-facing label reads as ~/.agenthud/summary-prompt.md
  on every platform. (Pure cosmetic on POSIX; lets the Windows
  CI tests pass.)

v0.12.0 was tagged but never reached npm — the Windows test job in
CI caught this issue before the publish step ran. v0.12.1 is the
first 0.12 release on npm.