fix: windows dev setup

[janburzinski]

Description

• makes dev/debug scripts cross-platform with cross-env
• replaces posix-only cleanup commands with node-based scripts
• cross-platform dev database reset command

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 makes the desktop app dev scripts work across platforms. The main changes are:

• cross-env for dev and debug environment variables.
• Node-based cleanup and database reset scripts.
• Lockfile updates for the new dependency.

Confidence Score: 5/5

This looks safe to merge after a small cleanup to database reset path handling.

• The changed dev scripts use a dependency that matches the repo's supported Node version.
• The cleanup script keeps the previous package-relative behavior.
• The database reset script can miss the runtime dev DB when HOME is overridden on macOS.

apps/emdash-desktop/scripts/db-reset.ts

Important Files Changed

Filename	Overview
apps/emdash-desktop/package.json	Replaces POSIX-only dev, clean, and reset commands with cross-platform script entries.
apps/emdash-desktop/scripts/clean.ts	Adds a small Node cleanup script for package-local node_modules and dist targets.
apps/emdash-desktop/scripts/db-reset.ts	Adds a cross-platform default dev database reset script, with a path edge case when HOME differs from Electron's app-data base.
pnpm-lock.yaml	Adds resolved dependency entries for cross-env and its transitive packages.

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

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### Issue 1 of 1
apps/emdash-desktop/scripts/db-reset.ts:12
**HOME Overrides Miss Runtime DB**

When `HOME` is overridden on macOS, this script deletes `$HOME/Library/Application Support/emdash-dev`, while the Electron app's `userData` path is derived from the platform app-data directory. In that state `pnpm run db:reset` can print success while the real dev database remains unchanged, leaving the stale or corrupt DB in place.

_{Reviews (1): Last reviewed commit: "fix(dev): clean electron build output" | Re-trigger Greptile}