fix: initial prompt on windows

[janburzinski]

Description

• fix windwos stdin prompt piping
• use powershell wrapper on windwos instead of bash piping
• normalize extentionless npm shims to .cmd when needed

Screenshot/Recording (if applicable)

https://cap.link/cyk5zsndre368ng

Checklist

• I kept this PR small and focused
• I ran a self-review before opening this PR
• I ran the relevant local checks or explained why not
• I updated docs when behavior or setup changed
• I added or updated tests when behavior changed, or explained why not
• I only added comments where the logic is not obvious
• I used Conventional Commits for commit
  messages and, when possible, the PR title

[greptile-apps]

Greptile Summary

This PR fixes Windows stdin prompt delivery for local agent commands. The main changes are:

• Adds platform-aware command building for local and SSH conversations.
• Uses a Windows PowerShell wrapper with temp-file stdin redirection.
• Keeps POSIX stdin prompts on the existing bash pipeline.
• Adds optional byte-based prompt spilling support and tests.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
packages/core/src/agents/plugins/helpers/standard-command.ts	Adds platform-aware stdin wrapping and a Windows temp-file redirection path for stdin-pipe prompts.
apps/emdash-desktop/src/main/core/conversations/spill-large-prompt.ts	Adds an optional byte threshold for prompt spilling while keeping the production default disabled.
apps/emdash-desktop/src/main/core/conversations/impl/local-conversation.ts	Passes the local platform into command construction.
apps/emdash-desktop/src/main/core/conversations/impl/ssh-conversation.ts	Uses the POSIX command path for SSH conversations.

_{Reviews (3): Last reviewed commit: "fix(agents): format windows stdin test" | Re-trigger Greptile}

[janburzinski]

@greptileai

[janburzinski]

@greptileai